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Weight regulation 4: Low carbohydrate vs. low fat lifestyles for weight loss and maintenance

After my digression into the 2010 Dietary Guidelines I am resuming my series on weight regulation with a comparison of the two major methods of achieving weight loss. I was tempted to call these weight loss diets but to regulate weight in the long term it is necessary to make a lifestyle change.  One can’t go on a diet and then go back to eating the way she always did and expect to maintain the weight loss.  Let me state at the outset that both of these methods work for taking off weight.  However, there is great metabolic variability among people; one size does not fit all.

Most people are familiar with low calorie diets.  These are the ones recommended by the majority of physicians, dietitians and weight loss programs like Weight Watchers.  They subscribe to the idea that calories taken in must be less than calories expended.  Generally, women are limited to about 1200 calories a day and men to about 1500, and it is recommended that a weight loss of 1 to 2 pounds a week is optimal.  In order to keep the calories down to those levels it is necessary to strictly limit fat consumption because of its higher caloric density.  Therefore, low fat diets are by necessity high carbohydrate diets, since protein intake should optimally be kept around 15-20% of calories. High carbohydrate diets must be calorie restricted because of our ability to easily over-consume carbohydrates. Sticking to the diet requires strict monitoring of intake, sometimes even weighing and measuring of all food.  These eating regimens result in weight loss for many people but some find that they do not lose when following this plan, probably due to the excessive insulin produced in order to clear large amounts of glucose from the blood.  Since calories are curtailed the body often goes into panic mode, thinks that it is starving, and begins to conserve energy.  The whole metabolism can slow down and with it weight loss. Calorie restriction leads to calorie conservation by the body, making it much harder to lose or maintain weight. Once the weight is lost it is necessary to follow a restricted calorie plan in order to maintain the weight loss.

Low carbohydrate diets are much less familiar to us and have been, until recently, perceived as dangerous, faddish, and unsuccessful in the long term by medical and nutrition experts.  Basically, the low carbohydrate diet must be higher in fat to make up for the uneaten carbohydrates.  It may be slightly higher in protein but is not a high protein diet.  Excess protein, beyond what the body needs for growth and repair of tissues, will be converted to glucose and used for energy, a waste of an expensive nutrient.  The idea behind this diet is that the body learns to use fat for its energy needs rather than glucose, thereby driving body fat out of storage.  Ingested fats are also used for energy needs as well as structures.  Carbohydrate restriction, not negative energy balance, is responsible for initiating the metabolic response to fasting.  In one study (Klein & Wolfe, 1992) infused lipids did not alter the breakdown of fat stores in fasting individuals.  In other words, in the absence of carbohydrate, ingested fat is not stored and doesn’t prevent the body’s use of stored fat.  Low carbohydrate diets are much less likely to initiate a starvation response by the body.  Therefore, once the weight is lost the dieter can add back just enough carbohydrates to maintain weight but otherwise does not need to restrict calories.

Many think of the low carbohydrate diet as being initiated by Dr. Atkins in the 1970s but forms of this dietary approach have been around for about 150 years.  Until about 10 years ago, however, no one had done any experimental studies of low carbohydrate diets to find out what the real effects are, even though there were thousands of anecdotal accounts of weight loss without hunger and without calorie restriction on these diets.  The first scientific study (Foster et al. 2003) compared the low carbohydrate diet recommended by Atkins with a standard low-fat low- calorie diet in two groups of overweight subjects.  Their results showed that the people on the low carbohydrate diet actually consumed more calories per day, lost more weight over 6 months, and also had higher HDL cholesterol and lower triglyceride levels than the subjects on the low calorie diet. This study has been followed by several more (e.g. Volek et al. 2004, Gardner et al. 2007, Shai et al, 2008) that essentially have shown the same thing—more weight loss and better lipid profiles on a low carbohydrate diet.  It wasn’t the dietary fat that mattered, it was the carbohydrate.

To sum up, low carbohydrate diets are not usually calorie restricted because they are naturally self-limiting.  Low-fat low-calorie diets must be calorie restricted because of our ability to over-consume carbohydrates, and because of what carbohydrates do to our insulin levels.  Both of these regimens work for weight loss, as least in some people.  In general, many health-related biomarkers improve with weight loss on either regimen, but consistently studies find higher HDL levels and lower triglyceride levels in subjects on low carbohydrate diets. Both can be nutrient dense if the correct whole unprocessed foods are chosen.  Low carbohydrate does not meant no carbohydrate.  It is most efficacious when lots of vegetables and some fruits are eaten, but starchy vegetables and flour products are avoided.  The fats eaten on both diets should be the natural variety—butter, olive oil, coconut oil, lard, and not the highly processed vegetable oils and margarines.  Low-calorie diets must make every calorie count by using whole, nutrient-dense foods and eliminating highly processed sugar and starch-laden options.  Finally, either we reduce carbohydrates and eat more natural fats, or we eat more carbohydrate and cut back on fat. To work long term either regimen must be followed for life.  High carbohydrate cannot be combined with high fat—that’s a recipe for weight gain. As far as long-term health and ease of weight maintenance goes it looks like low carbohydrate higher fat is the winner here, but like I said, everybody is different.

The 2010 Dietary Guidelines: Are they really about our health?

This post includes my testimony to the Dietary Guidelines Advisory Committee (DGAC), established by the U. S. Department of Agriculture (USDA) and U. S. Department of Health and Human Services (HHS) to update the previous (2005) Guidelines.

The 2010 Guidelines make four broad recommendations:

Consume fewer calories and engage in more physical activity.

Switch to a diet that is primarily plant-based (vegetables, beans, peas, fruits, whole grains, nuts, and seeds), along with seafood and fat free and low-fat dairy, and only moderate amounts of lean meats, poultry and eggs.

Avoid or greatly reduce consumption of foods containing added sugars and solid fats because these dietary components contribute excess calories and few, if any, nutrients. Reduce sodium and refined grain intake.  Reduce saturated fat intake to no more than 7% of calories and cholesterol to 200 mg per day.

Get regular exercise: for adults, 2.5 hours per week of activity at the brisk walking level, or 75 minutes at the jogging or swimming level; for kids through teens, an hour a day of some mix of these activities.

The 2010 USDA Dietary Guidelines continue the same basic recommendations that have been touted for the last 30 years.  They state at the outset that the majority of the American public is overweight or obese and yet undernourished in several nutrients.  They also state that most people are not following the previous guidelines.  I fully agree with the statement that “good health and optimal functionality across the life span are achievable goals but require a lifestyle approach including a total diet that is energy balanced and nutrient dense.”  But I differ on how to achieve these goals. My arguments are backed up by over 100 years of research that looks beyond observational studies and into the physiological mechanisms explaining our collective malnutrition, excess weight and poor health. Since Dietary Guidelines have been in place Americans have gotten appreciably fatter and more diabetic, and cardiovascular disease (CVD) is still the number one cause of death.

The Dietary Guidelines are based on several false premises: The first is that body weight is only a matter of calorie balance. The calorie is a physical measure of heat determined in a laboratory and has little to do with how the food will act in the body.  Energy partitioning is tightly regulated by hormones and genetics. Instead of a defect in calorie balance, excess weight may well be a defect in the regulation of fat metabolism; a disorder of fat accumulation, not necessarily of overeating. Insulin, an anabolic hormone, regulates the flow of energy in the body. The chronic elevation of insulin brought on by a high carbohydrate diet is the major contributor to weight gain, but there is no mention anywhere in the guidelines of blood sugar or insulin. Cells become resistant to insulin signals, the pancreas increases its insulin secretion to higher than normal levels and eventually muscle and other tissue cells become insulin resistant, but adipocytes remain inordinately sensitive to it. High glucose and insulin in the blood also cause triglycerides to remain locked inside the adipocytes. The body perceives this situation as starvation at the cellular level, hunger ensues, and more carbohydrates are eaten.1 Insulin and glucose levels are seldom low enough for fatty acids to be released for fuel when a high carbohydrate diet is eaten, as is recommended by the Dietary Guidelines. Low carbohydrate diets for weight loss and maintenance are only briefly mentioned in the Guidelines, yet many recent studies have shown their efficacy.2,3

The second false idea is that we should fear saturated fat. The 2010 Guidelines are recommending that we reduce our saturated fat intake even further, from 10% to less than 7% of total calories.  Saturated fat intake is not a predictor of CVD,4 nor is it associated with overweight by itself.  Foods high in saturated fat are nutrient dense (vitamin A in butter, vitamin D in lard, omega-3 fatty acids in grass fed beef) and are what our ancestors had been eating for thousands of years, before CVD became prevalent.  All the deleterious effects of saturated fat have been studied in the presence of high carbohydrate.  If carbohydrate intake is low the effects of saturated fat disappear.  Replacing saturated fat in the diet with carbohydrate worsens lipid profiles.5 Replacing it with polyunsaturated fats, predominantly the omega-6 fatty acids in vegetable oils, appears to ameliorate CVD, but most of the studies were confounded by changing too many other lifestyle factors at the same time.5 It is unconscionable that the DGAC lumps solid fats with sugar as substances to be avoided.  Trans fats have definitely been shown to be associated with CVD but are vastly different than natural saturated fats.  And to say that saturated fat is related to diabetes shows a woeful lack to understanding of basic biochemistry and metabolism.  It is particularly heinous to recommend low saturated fat diets for growing children.

Third, cholesterol levels do not predict heart disease.  As many people with lower than normal levels have heart attacks as people with higher levels.  Cholesterol is a very important substance in the body, necessary for building the nervous system, cell walls, hormones, vitamin D, etc.  There is no evidence that dietary cholesterol affects body levels, since the vast majority of cholesterol is synthesized in the body.  High LDL cholesterol can be a symptom of inflammation, which is related to CVD. But the remedy isn’t to lower cholesterol but to find and remove the cause of the inflammation (refined carbohydrates).  It borders on criminality to suggest that we should restrict dietary cholesterol in the diets of children who are growing and developing their nervous systems.  We will be rearing a generation of people with suboptimal intellectual as well as physical development.

Fourth, a plant-based diet is not a nutrient dense diet!  Human cells don’t differentiate between glucose molecules from whole grain bread or a candy bar. Fruits and vegetables are beneficial since they pack a lot of nutrients into fewer carbohydrates.  But whole grains are way over-emphasized, especially when whole grain foods are defined as having 51% whole grain, and whole grains contain phytates that block the absorption of minerals. There is no preformed vitamin A in plant foods, and the carotenes need fat to be absorbed and are very inefficiently converted to vitamin A in the body.  Vitamin D needs to come from animal food and, by the way, how can Vitamins A or D be absorbed from skim milk!  And there is no B12 in plant foods.  The most nutrient dense foods come from animals that have concentrated the difficult to extract nutrients from plants like grass into forms that humans can readily use. We are omnivores!  And we need the fats and proteins in animal foods for optimum functioning.

In summary, the government, nutrition and medical authorities need to stop pandering to the enormous agribusiness, food and pharmaceutical companies that fund their research.  What Americans need to eat is real food, nutrient dense animal foods like eggs, whole milk, fish, grass-fed meats with their full complement of omega-3 fatty acids and better lipid profiles, locally grown fruits and vegetables, and small quantities of properly prepared grain and legume dishes.  Only then will we be truly healthy.  Recommending partial foods like low-fat milk, egg whites, and ‘enriched or fortified’ refined grain products just perpetuates poor health. But unfortunately for the aforementioned stakeholders, there is no profit in healthy people, only in keeping us sick so that we will spend our dollars on doctor visits and lifelong drugs for chronic diseases.  Lets have a new paradigm and tell the American people not what industry wants them to hear but what they need to hear in order to take charge of their own health.  The dietary guidelines should be an ideal to strive for and not a compromise for politics and expediency.

References

1Taubes, Gary.  2007.  Good Calories Bad Calories. Challenging the Conventional Wisdom on Diet, Weight Control, and Disease. Alfred A. Knopf, New York.  601 pp.

2Gardner CD et al. 2007. Comparison of the Atkins, Zone, Ornish and LEARN diets for change in weight and related risk factors among overweight premenopausal women. JAMA 297: 969-977.

3Shai I et al. 2008. Weight loss with a low carbohydrate, Mediterranean, or low-fat diet. NEJM 359: 229-241.

4Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. 2010. Saturated fat, carbohydrate, and cardiovascular disease. AJCN 91: 502-509.

5Hu FB, Manson JE, Willett WC. 2001. Types of dietary fat and risk of coronary heart disease: a critical review.  J AM Coll Nutr 20:5-19.

Weight regulation part 3: What about carbohydrates?

Since the 1970s we have been told by a majority of nutrition and medical professionals that fat, especially saturated fat, is the culprit in all of our ills from obesity and cardiovascular disease to diabetes and cancer.  We have been urged to cut our fat intake down to abnormally low levels.  Since protein intake remains relatively stable, cutting down on fat means increasing our intake of carbohydrates. We have complied admirably and more and more of us have gained weight and become insulin resistant and eventually diabetic.  The remedy for this, we are told, is to cut calories and exercise more.  But this is a recipe for hunger, not tolerable in the long term, as well as a slower metabolism that tries to conserve energy. We have also been told that virtually no one has a hormone problem.  We just eat too many high calorie, high fat foods.

It is true that to gain weight we must take in more energy than we expend.  However, the way that our bodies partition the energy from the food we eat into either use or storage is tightly regulated by our internal chemical signals (hormones) and by genetics. What if, instead of a defect in calorie balance, excess weight is a defect in the regulation of fat metabolism; a disorder of fat accumulation, not necessarily of overeating?  The release of fat to be used as energy may be impeded or the deposition or synthesis of fat promoted, resulting in weight gain.  If an abnormal number of the calories we eat go into storage in our fat tissue, the rest of our body’s cells and tissues will perceive an energy deficit. Hunger and satiety are manifestations of metabolic needs and physiological conditions at the cellular level, and so they’re driven by the needs of our bodies, not our brains. Cells must receive sufficient energy to function; we eat to maintain the flow of energy to our cells and tissues.

The substance that regulates the flow of energy in our bodies is insulin, which is an anabolic or storage hormone.  Made in the beta cells of the pancreas, insulin is secreted into the bloodstream in response to glucose levels in the blood.  Carbohydrates in the form of starches (bread, rice, potatoes, corn, anything made of wheat flour, etc) all are digested into glucose, which passes from the digestive tract directly into the blood.  Sugar and high fructose corn syrup do the same, except they also contribute fructose. After eating carbohydrates the glucose level in the blood rises, stimulating the pancreas to release insulin.  Insulin is necessary for the transportation of glucose from the blood across the cell wall into the cell.  The more refined the carbohydrates and the more easily digestible they are the more and faster insulin is released.  It is this insulin that plays a primary role in the fattening process.  For it is the chronic elevation of insulin brought on by a high carbohydrate (especially refined carbohydrate) diet that is the prime suspect in the cause of weight gain.

A very simplified explanation of how this works might look like this.  Excessive carbohydrate intake, especially of processed carbohydrates, leads to chronically elevated insulin levels.  Cells become resistant to the insulin signals to let in the glucose, so the pancreas increases its insulin output in order to remedy the situation, resulting in higher than normal insulin levels.  This condition eventually develops into insulin resistance. Interestingly, muscle and other tissue cells become insulin resistant but the fat cells (adipocytes) remain inordinately sensitive to it, meaning that the excess glucose in the blood is transported into adipocytes where it is converted into fat (triglycerides) for storage.  In fact, glucose is not only converted to fatty acids, it is also necessary in order for fatty acids to be assembled into triglycerides. High glucose and insulin in the blood also cause the triglycerides to remain inside the fat cells where they cannot be broken down for energy.  So we have plenty of stored fuel within our fat cells but it is not accessible to be used for energy as long as we have high levels of glucose and insulin in our bloodstreams.  Our body perceives this situation as starvation at the cellular level, hunger ensues, and we eat more.  Fatty acids can only be released into the bloodstream to be used for fuel when insulin and glucose levels are low.  And they are seldom low if we eat a high carbohydrate diet.  Our insulin levels are elevated for longer periods than nature or evolution intended, and we fail to balance fat oxidation with fat deposition.  So the problem of inordinate weight gain may well be hormonal for most of us! Incidentally, it is normal to burn fatty acids for most of our energy needs.  They are the logs on our metabolic fire.  Glucose acts more like the kindling, burning quickly and fueling a desire for more.

So far we have talked about glucose, but what about fructose?  While fructose does not raise insulin levels, it is transported directly from the small intestine to the liver.  In the liver it enters the metabolic pathway that builds fatty acids and triglycerides.  Thus fructose is considered the most lipogenic (fat-building) carbohydrate.  Sugars such as sucrose (table sugar, 50% glucose, 50% fructose), high fructose corn syrup (usually 55% fructose, 45% glucose) and agave syrup (75-90% fructose) stimulate fat synthesis more than glucose alone.

It has been said that it is impossible to gain weight on a diet devoid of carbohydrates.  The efficacy of low carbohydrate diets for weight loss has been shown both anecdotally and experimentally (more about these in future posts).  The answer for most of us, however, comes back to the ongoing theme of this blog—eat real food.  Vegetables are predominantly carbohydrates but are not concentrated or refined and come packaged with many other nutrients and fiber.  Fruits contain fructose but in moderate quantities.  If made into juice, however, the sugar content is concentrated many times over. Moderate quantities of whole starchy foods are fine unless you need or want to lose weight or suffer from insulin resistance or diabetes.  Generous quantities of meats, eggs, natural fats, unsweetened dairy products, vegetables and fruits do not cause weight gain unless combined with refined carbohydrates!

And why, you might ask, do the medical and nutritional experts advise us to eat more carbohydrates?  If I were a conspiracy theorist I might think that the generous contributions and research grants they receive from the big food companies that are so good at turning out a myriad of cheap processed high carbohydrate foods has something to do with it.  Also, if we eat a diet high in refined carbohydrates we will eventually become sick and need pharmaceutical intervention.  There is lots of money to be made by keeping us sick and treating us for it!

Reference

Taubes, Gary.  2007.  Good Calories Bad Calories. Challenging the Conventional Wisdom on Diet, Weight Control, and Disease. Alfred A. Knopf, New York.  601 pp.

Weight regulation part 2: Does dietary fat make us fat?

The calorie theory of weight regulation holds that in order to maintain a stable weight we must eat the same number of calories as we expend over time.  If we want to lose weight then we must eat fewer calories than we expend.  Since fat contains 9 calories per gram and carbohydrate and protein each contain 4 calories per gram, theoretically we can eat a larger volume of food if we eat a low fat diet.  Most obesity researchers and health authorities recommend the low-fat low-calorie diet as the best method of weight control.  However, there are problems with this scenario.  I will begin to address them in this post.

As background, epidemiological studies show no evidence linking obesity to dietary fat intake either in the same population or between different populations. Our dietary fat intake in the US has decreased since the 1970s but we have gotten fatter. Studies showing that certain strains of rats and mice gain weight on high fat diets actually compared diets high in carbohydrates with diets high in both fats and carbohydrates.  But some strains of rats do not grow obese on high fat diets, and those that do get much fatter on high-fat high-carbohydrate diets than on high-fat low-carbohydrate diets.  These studies also used far higher proportions of fat than rodents would normally consume, and most of them used vegetable oils as their fat source.  Also, when rats are allowed to eat all they want of the standard American diet of supermarket foods they grow very fat, but the foods they consume in excess are sugars and carbohydrates; high fat foods like cheese and peanut butter are self-limiting.   Finally, studies that have attempted to cause weight gain in human subjects have found that it is impossible to cause people to overeat on diets high in fat and protein, but easy to cause them to eat several thousand extra calories a day when the food contains mainly carbohydrate.  How much meat and butter can one eat without losing appetite?  How many cookies, chips, crackers and other carbohydrate foods can one eat and still be hungry for more?  Diets that limit carbohydrates but allow unlimited protein and fat work for weight control for these very reasons.  I’ll go into this topic when we get to carbohydrates in my next post.

There are physiological reasons for the satiating qualities of fat.  Hormones in the small intestine sense the presence of fat and turn off hunger.  Leptin is up-regulated, telling our bodies that we have eaten enough; ghrelin is down-regulated, telling us that we are no longer hungry.  Fat is also slower to digest, causing us to feel full longer. Lack of fat in our diet tells our bodies that food is scarce and we had better hold on to our fat stores.  We get hungry sooner and may crave fried food.  Evolutionarily, fat is our preferred fuel.  It signals the body that we are not starving, that food is abundant, and that our bodies can use our own stored fat for fuel. When our bodies are deprived of fat they get very efficient at converting carbohydrates to fat.

Some interesting recent studies are pointing to one type of fat as a contributor to obesity.  While only investigated in mice and rats so far, it appears that a disproportionally high ratio of omega-6 to omega-3 polyunsaturated fatty acids causes rodents to become obese, grow a larger number of adipocytes (fat cells), and suffer liver damage.  Linoleic acid, an omega-6 fatty acid, is converted to endocannabinoids that trigger appetite in both rats and humans.  We have been encouraged to substitute vegetable oils and margarines, which are disproportionately high in omega-6 fatty acids, for traditional fats like butter and lard, which have only small amounts of omega-6 fatty acids.  Could the same process be happening in humans? We have been subject to a vast experiment in non-traditional eating.  Is it making us fat?  These rodent studies are certainly suggestive of a reason for weight gain in those who indulge in foods high in vegetable oils or fried in them, but the actual mechanism is not known, nor have human studies been done.

All fats are mixtures of fatty acids.  In general the vegetable oils have a very small amount of omega-3 fatty acids and large amounts of omega-6 fatty acids. Natural fats like butter, lard, coconut oil, olive oil, beef and chicken fat have higher amounts of saturated and monounsaturated fatty acids and very little omega-6 or omega-3 fatty acids.  However, if animal fats come from grass fed animals they have higher amounts of omega-3 fatty acids than if they come from grain-fed animals.  Do not be afraid of saturated fatty acids—they have nothing to do with heart disease (more on this later).  While both linoleic acid (omega-6) and alpha-linolenic acid (omega-3) are dietary requirements (essential fatty acids), they are required in very small amounts and will be retained and used more efficiently if the diet includes plenty of saturated fatty acids.

The bottom line is that we need fats in our diet.  They play vital roles in the body and form important structures; from the walls of our cells to the sheaths around our nerves to most of our brains.  We cannot live without them and we are much healthier if we eat them in adequate amounts.  They are calorie dense but at the same time are satiating and self-limiting if they are from the traditional sources listed above.  So if fat is not the culprit in weight gain, with the possible exception of vegetable oils, what is?  Stay tuned for my next post on carbohydrates.

References

Taubes, Gary.  2007.  Good Calories Bad Calories. Challenging the Conventional Wisdom on Diet, Weight Control, and Disease. Alfred A. Knopf, New York.  601 pp.

Hanbauer, Ingeborg, et al. 2009.  The decrease of n-3 fatty acid energy percentage in an equicaloric diet fed to B6C3Fe mice for three generations elicits obesity.  Cardiovascular Psychiatry  & Neurology. Publ. online 9/16/09.

Ailhaud, Gerard, et al. 2008. An emerging risk factor for obesity: does disequilibrium of polyunsaturated fatty acid metabolism contribute to excessive adipose tissue development? British Journal of Nutrition 100:461-470.

Weight regulation part 1: Why have we gotten so fat?

Americans have seen a rapid increase in weight gain and subsequent overweight and obesity over the last 30 years, and the rest of the world is catching up fast. Most of the medical and nutrition establishment maintains that it is because we eat too much and exercise too little, and most programs to fix the obesity problem are based on this premise.  But usually this simplistic approach doesn’t work long term. Ninety-five percent of people who lose weight gain it back within a short time. In this first post on weight regulation I will point out some of the complicated intertwining aspects of the problem and then describe many of them in detail in subsequent posts.

What has changed since the 1970s? Our genetics are basically the same as those of our distant ancestors who evolved over the millennia on a diet of wild meat, fish, fruits and vegetables, which had to be chased down and killed or harvested by hand. The human penchant for sweet, salt and fat led to survival, as foods with these tastes generally contain more energy, a much sought after commodity in the distant past.  We evolved to store this energy as fat during times of plenty to tide us over the times of scarcity, and for most of our history this assured our survival and health. Equally important, until about 150 years ago we were eating mostly traditional diets of whole local foods. The switch to industrial foods happened gradually but the rates of overweight and obesity remained relatively constant until about the 1970s. Over the last 30 or so years something in our environment drastically altered the way we eat. The genetic traits that were beneficial in an environment of food scarcity and nutrient-dense foods are now causing us to eat way too much nutritionally inferior food.  A large amount of research has tried to elucidate this phenomenon. What follows are some of the most significant areas.

Is it one of the macronutrients?  What about dietary fat?  This is a popular notion, based on the fact that fat contains more than twice as many calories per gram as do protein or carbohydrate.  And ingested fat goes straight to the fat cells, right? But we have been told to eat less fat since the 1970s, statistics show that we have been doing it, and yet we are getting fatter.  We have replaced dietary fat with carbohydrates, many of them refined and processed. Is it carbohydrates, then?  If so, is it starch, which consists of long chains of glucose molecules, or is it sugar (e.g., sucrose and high fructose corn syrup)?  But aren’t these used directly for energy and only stored as fat with difficulty?  What about protein?

The calorie theory of weight regulation maintains that calories in must equal calories out in order to maintain weight.  It doesn’t matter what the calories come from.  This works in physics (second law of thermodynamics) but the human body is a complex organism with many other factors, such as hormones, neurotransmitters, immune factors, and chemical messengers at work.  All calories may not be equal.  For example, glucose stimulates insulin secretion, which suppresses appetite, but it is an anabolic hormone, i.e., it facilitates energy storage. Fructose doesn’t require insulin, doesn’t suppress appetite, and is converted directly to fat for storage. Also, exercise to precisely burn off calories eaten is a very precarious premise.  All types of exercise are not equal either.  Even more importantly, people are different.  We all need certain basic nutrients but, depending on our unique metabolisms, can best reach and maintain our weight on different combinations of whole natural foods.

Have we been taking in more calories over the last 30 years?  Research shows that we have.  Why? The following are some of the reasons. Food is easily accessible 24/7 and food manufacturers are very good at making sure, through advertising and product placements, that we are constantly aware that we might want to eat some of it. We eat out more, and when we eat at home we use a lot of prepared food.  This has come about as our lives have gotten busier and more stressful, another correlate with weight gain.  We also get less sleep.  Food manufactures are extremely good at figuring out how to make us eat more—the old sweet, salt and fat combined with very realistic chemical flavoring agents.  This leads to hyper-palatability and excessive intake.  We are exposed to many more chemicals in our environment than in earlier times.  Some of them are hormone disrupters.  We are urged to be super clean and disinfect everything.  We take antibiotics and other drugs, which interfere with our gut bacteria.  Gut bacteria have been shown to differ between obese and lean individuals.  And they might even be catching!  Most of us are deficient in vitamin D.  Can sufficient vitamin D lead to weight loss? Anecdotal evidence shows that it can.  There is evidence for calcium too.  What about glycemic index?  High glycemic index foods raise blood sugar faster and higher, necessitating increased insulin secretion, which then leads to a crash in blood sugar and ensuing hunger.  The energy density (calories per gram), huge portion sizes, and sheer variety of foods available to us are also contributors. Lastly, fiber intake has been shown to be beneficial for weight regulation, but what type, how much, and where should it come from?

Confused yet?  Stay tuned.  I intend to show the mechanisms for many of these ideas over the next several posts.  In each instance I will also explain how a return to a real food diet can circumvent many of these problems and lead to a stable healthy weight.

The meat controversy—biology, ecology and ethics

First lets look at meat eating from a biological point of view. Humans are omnivores.  From the length and architecture of our digestive tracts to our nutritional requirements we maintain the best health on a diet that includes both animal and plant foods.  In fact our hunter-gatherer ancestors ate far more meat and fat as a proportion of their diet than we do today.  With the advent of agriculture and the consequent consumption of a grain rather than a meat based diet our ancestors lost and inch or two of height and their skeletons became less robust.  There was a slight rebound in bone size with the domestication of animals.1

Protein from meat, milk and eggs is termed complete protein because it contains all of the amino acids in the same balance that they are found in the human body.  Therefore they are efficiently absorbed and utilized, unlike plant proteins, which are universally low in one or more amino acids and are used much less efficiently. Looking at specific nutrients, vitamin B12 is found only in animal protein.  There are no vegetable sources.  B12 deficiency leads to pernicious anemia with resultant permanent neurological damage.  Vitamin A is also found only in animal foods.  Beta carotene is found in plant foods but is very inefficiently converted to vitamin A in the body.  Most minerals are found in much higher levels in animal foods and are more available because they are not blocked from absorption by phytates as they are in most plant sources.

Much ado was generated in the media last year when a study was published in the Archives of Internal Medicine that concluded, “red and processed meat intakes were associated with modest increases in total mortality, cancer mortality, and cardiovascular disease mortality.”2 In this study, which was a large epidemiological study of about 500,000 AARP members aged 50-71, participants filled out a food frequency questionnaire asking about their food intake for the previous year.  From personal experience I know how difficult these questionnaires are to answer accurately, and I am well versed in nutrition and conscious of what I eat!  So to begin with the data are suspect. In addition, it is the nature of an epidemiological study to find correlations or associations between variables, but in no way can it identify causation.  Interestingly, the researchers found that meat eaters were more likely to smoke, took in more calories, were heavier, had a lower educational level, were less likely to exercise, and ate fewer fruits and vegetables.  Might these be more important associations of their higher mortality?  But what I find totally missing from this study is any analysis of the processed carbohydrate intake of these subjects.  Might it be that, since ‘everyone knows’ (given current misguided dietary advice) meat is unhealthy, the more health-conscious subjects were eating less meat but were also engaging in other positive health behaviors?  The people eating more meat were probably also eating more white buns, sugar, soda, and French fries (hydrogenated oil) and other unhealthy foods not accounted for in this study.  The authors do admit that the associations of meat eating with disease were modest.  Had they accounted for processed carbohydrates and trans fats in their analyses I postulate that the associations would have disappeared!

Another problem with epidemiological studies is that they compare the diets that people actually say they eat, and the vast majority of American food intake is sub-optimal. Virtually all of the people in this survey were eating CAFO (concentrated animal feeding operation) meats, since this type of meat is universally sold in grocery stores. How beef, pork, chicken, and lamb are raised is very important for nutritional quality.  CAFO meat is higher in omega 6 fatty acids and lower in omega 3 fatty acids and has more obnoxious chemicals stored in its fat than meat raised organically on pasture. But grass fed and naturally raised meat can’t be assessed in epidemiological studies because too few people are consuming it.

From an ecological perspective the raising of meat can be a sustainable operation that enhances rather than damages the environment.  Cattle, pigs, chickens and lambs are meant to roam free outdoors and eat a variety of foods.  Cattle and lambs do best on grass, pigs eat a variety of foods and chickens are meant to eat grass and insects as well as grain.  When sustainably raised the animal waste fertilizes the soil and enhances the grass pastures that enrich the animals.  Everything is used and reused.  Marginal land that is not suitable for plowing will often grow lush grass and sustain grazing animals.

Detractors of meat eating purport that consuming mostly plants is better for the environment.  They may cite the current industrial model for raising meat, in which corn and soy are fed to cattle in order to fatten them faster. Grass is the natural diet for cattle, not grain.  They may fatten fast on grains but they also experience health problems.  These illnesses along with the crowding of the animals necessitate frequent antibiotic and pesticide treatment, and often result in contaminated meat.  The waste matter that is generated from the unnatural diet and crowded conditions is not recycled and creates massive pollution problems. But in growing the grains that sustain a plant-based diet, our current industrial agriculture system, which uses mega farms growing monoculture crops of genetically modified grains, depends heavily on petroleum-based fertilizers and pesticides.  In the process of growing these grains countless native species of birds, small mammals, reptiles, amphibians, and beneficial insects and worms are exterminated and many are on the brink of extinction.  The consumption of these crops of soy, wheat and corn, mainstays of a plant-based diet, therefore probably does more environmental damage than consuming animals raised on their natural foods.

Finally, the ethics of eating meat is a non-argument.  That’s the way life works.  Eat or be eaten.  We humans tend to think that only mammals and maybe birds are important, but when you consider all of the small animals and native plants killed or displaced by our current system of growing grains you realized that to live is to eat and to eat something has to die.

What is the answer? Eat meat for robust health. If possible find meats and poultry raised humanely on sustainable farms. If enough of us demand sustainably raised meats the food/agriculture industry will eventually get the idea.

1Cohen, M.C. 1989. Health & the Rise of Civilization. Yale Univ. Press, New Haven, CT. 285pp.

2Sinha, R, AJ Cross,; BI Graubard, MF Leitzmann, A Schatzkin 2009. Meat Intake and Mortality: A Prospective Study of Over Half a Million People. Arch Intern Med 169:562-571.

Healthcare in Cuba: an interesting comparison

This post is taken from a recent article1 in Science magazine. The US trade embargo with Cuba reaches 50 years this year.  During this time food, drugs and medical supplies flowing from the US to Cuba have been severely restricted.  After the collapse of the Soviet Union in 1989, foreign aid to Cuba faltered and the health of the Cuban people suffered.  By the end of the 20th century few international pharmaceutical companies sold medicines or the raw materials to make them to Cuba.

Despite the impacts of these sanctions on the Cuban economy, effects on the health of the population have been offset by the positive aspects of their healthcare system. Cuba has produced health outcomes comparable to most of the developed countries in terms of life expectancy, physicians per capita, and infant mortality.  And they have done it at a government expenditure of $355 per person (2006), compared to $6714 (public plus private) for the same year in the US.  The success of Cuban health care is due in large part to their emphasis on disease prevention and enhanced primary health care, which have been cultivated during the trade embargo.

“Cuba has one of the most proactive primary health care systems in the world.  By educating their population about disease prevention and health promotion, the Cubans rely less on medical supplies to maintain a healthy population. The converse is the United States, which relies heavily on medical supplies and technologies to maintain a healthy population, but at a very high cost.”1

The Cuban medical education system emphasizes primary care and encourages young doctors to work in rural areas.  About 65% of new doctors choose primary care as a career path, the remainder enter specialty training. Cuba has also created an infrastructure in the form of community-based clinics to support primary care physicians. By contrast, in the US about 20% of new doctors choose primary care, the rest specialize, and the system supports the specialists, both monetarily and psychologically.2 “This emphasis on primary-care medicine, community health literacy, universal coverage, and accessibility of health services may be how Cuba achieves developed-world health outcomes with a developing-world budget.”1

The Science article does not say anything about diet, except that Cuba has experienced some food shortages during the embargo.  It seems reasonable to speculate that at least part of their good health may stem from the lack of imported industrial food.  The embargo on food imports from the US was lifted in 2000, so it will be interesting to see if the health gains in Cuba are sustained into the future.

1Drain, P.K. and M. Barry. 2010. Fifty years of U.S. embargo: Cuba’s health outcomes and lessons. Science 328: 572-3.

2Bodenheimer, T. 2006. Primary care—will it survive? New England Journal of Medicine 355:861-4.

Weston A. Price, DDS: a pioneer

Dr. Weston A. Price had a successful conventional dental career from about 1890 to the early 1900s, and devoted much of his time to the study of root canals.  This led him to the hypothesis that susceptibility to tooth decay came from a ‘disease’ or dysfunction inside the body, not from bacteria on the teeth.  In other words the teeth were not getting the nutrients they needed to be healthy, and this idea fostered Price’s interest and research in nutrition.

By the mid-1920s Price came to believe that conventional dentistry was only treating the symptoms of tooth decay and poor orthodontic structure that the increasingly industrialized and refined diet was promoting.  White flour and sugar, polished rice, margarine, pastries etc. had become an increasing part of American and European diets since the mid 1800s.  Discovery of the various vitamins and minerals in the early part of the 20th century showed just how nutrient poor these foods were.  These discoveries also prompted Price to do research on the relation of various vitamins and minerals not only to tooth decay but also such diseases as pneumonia and heart disease, and he began to think that poor nutrition was the basis for disease.

But he needed a control group to test his theories and he could not find one among the ‘modernized’ people who lived in ‘civilized’ society.  So he travelled the world during the 1930s seeking “remnants of primitive racial stocks” that still ate their traditional diets and led more physically demanding lifestyles.  This work culminated in his 1939 book, Nutrition and Physical Degeneration.  In essence he visited 14 groups of isolated people from all over the globe who still ate their traditional diets, analyzed and photographed their teeth, and compared them with nearby people of the same racial stock who had succumbed to diets of modern foods. He recorded the primitive diets and took samples of the foods back to his laboratory for analysis of vitamin and mineral content.

Though the diets of these far-flung primitive groups varied widely they had characteristics in common.  They consisted of whole foods that contained ample protein and animal fats high in fat-soluble vitamins (meat, especially organ meats, whole milk products, eggs, fish, seafood, insects), vegetables high in minerals, and no refined or devitalized foods.  After he had analyzed the food samples in his lab he found them to contain at least 4 times the quantity of water-soluble vitamins (C, B complex) and ten times the amounts of vitamins A and D as the American diets of his day1.  Besides their splendid teeth, Price noted the almost complete lack of degenerative disease and superb physical development of the traditional peoples.

Such was not the case with racially identical people of all the groups studied who had been introduced to what Price called the “foods of modern commerce” (sugar, refined flour, polished rice, canned goods, and refined vegetable oils).  These people showed the same decayed teeth, deformed jaws, susceptibility to infectious and degenerative diseases and painful childbirth that occur in modern societies.  And the children of these parents also showed similar deformities to the American and European patients Price saw at home.

Price was not alone in his thinking that good nutrition could prevent dental and physical degeneration.  There were a number of researchers contemporary with Price whose work was scientifically rigorous but who were professionally marginalized and at times considered “food faddists”.  Price and others hoped that the dental and medical professions would become less necessary with the advent of greater understanding of nutrition, food and agriculture.  In other words he was telling his fellow medical professionals in the 1930s and ‘40s that the growth and respectability of their professions was just a symptom of the industrial food system!

Fortunately, there has been a recent resurgence of interest in Price’s research and ideas, especially given absurdly spiraling health care costs and current epidemics of obesity, diabetes, heart disease and cancer.  But, as usual, follow the money.  There is no profit in prevention, only an improved quality of life for those who practice it.

1Price, Weston A. Nutrition and Physical Degeneration.  (La Mesa, CA: Price-Pottenger Nutrition Foundaton, 2006 [1939]. 524 p.

Lets start at the beginning…

Of course much nutritional damage begins generations before we are born, but we will leave that for another post.  As a practical starting point, what and how we feed our babies is crucially important to their future health.  In a recent analysis1, Bartick and Reinhold (2010), publishing in Pediatircs, concluded that

“If 90% of US families could comply with medical recommendations to breastfeed exclusively for

6 months, the United States would save $13 billion per year and prevent an excess 911 deaths,

nearly all of which would be in infants ($10.5 billion and 741 deaths at 80% compliance).”

Currently, only 12% of babies are exclusively breastfed at 6 months, and only 56% of babies are exclusively breastfed at 2 days of age!

Breast milk is the first ‘real food’ that an infant eats.  Since it comes directly from the mother’s body human milk is alive.  Beneficial bacteria in human milk populate the baby’s intestinal tract with the correct type of gut flora.  Breast milk also contains the proper proportions and types of protein, fat and carbohydrates for growth and development, hormones and enzymes for proper digestion and utilization of the milk, and antibodies and lymphocytes from the mother to protect the infant from disease.  Furthermore, the taste varies from day to day depending on what the mother ate, accustoming the baby to the tastes of food.  Also, the composition of the milk changes as the baby grows, keeping up with his need for nutrients.

Volumes have been written about the benefits to the baby of mother’s milk.  Although the current recommendations from the American Academy of Pediatrics and the World Health Organization include exclusive breastfeeding for the first 6 months and breastfeeding supplemented with weaning foods until the child is 1-2 years old, we are still being told by the medical and formula industries that formula fed babies do just as well as breastfed babies, and that if you cannot or choose not to breastfeed your baby she will still be healthy.  But will she? Bartick and Reinhold looked at 10 different childhood diseases (necrotizing enterocolitis, ear infections, gastroenteritis, hospitalization for lower respiratory tract infections, atopic dermatitis, sudden infant death syndrome [SIDS], childhood leukemia, childhood asthma, type 1 diabetes, and obesity).  Their cost savings are based on the lower likelihood that breastfed babies will contract these serious illnesses or die from them.

This scenario is but one example of the current dichotomy in our nutrition and healthcare systems.  As always, follow the money.  If mothers breastfeed they don’t buy formula and bottles, meaning less money for formula and bottle manufacturers.  If breastfed babies don’t get sick as often or as seriously their parents pay less money to the healthcare and pharmaceutical industries.  If we are serious about lowering healthcare costs in the US, a good beginning would be to encourage as many mothers as possible to breastfeed exclusively for the first 6 months and to continue until the child is ready to stop.

Successful breastfeeding is a matter of attitude, information, support, and good nutrition.  It also may require changes to maternity leave policies, and improvements in facilities that allow breastfeeding mothers to comfortably express milk during working hours. Our society’s overall attitude toward mothers breastfeeding in public places is slowly becoming more accepting, but we have a long way to go before mothers will feel totally at ease.  This seems to be an American hang up.  Most of the rest of the world has no problem with it.

1Bartick, M and A. Reinhold. 2010.  The burden of suboptimal breastfeeding in the United States: A pediatric cost analysis.  Pediatrics, 125; e1048-e1056; originally published online Apr 5, 2010.

How did we get here?

Important changes to our food supply have taken place over the last 150 years that have had profound effects on our health.  In this first post I will briefly cite some examples of these changes and then explore them and their health effects in more depth in subsequent blogs.

Bread:  Prior to the widespread adoption of roller milling in the 1870s wheat or rye for this staple food was ground between stone wheels and resulted in whole meal flour containing the starchy endosperm, germ and bran. Roller milling allowed the bran and germ to be separated from the white starch efficiently and cheaply. White bread and other baked goods were now available to the general population, not just the upper classes.  Vitamin deficiency diseases soon followed, but more subtle declines in health have taken longer to manifest themselves.

In the 1950s bakers realized they could save money by shortening the time it took to proof bread.  By increasing the amount of yeast they could produce loaves of bread in 3 hours instead of the slow 8-hour or more fermentation process used before that.  Today commercial breads can be produced in 40 minutes using rapid rise yeast, proofing agents, and accelerants.  However, when gluten, the protein in wheat, is improperly prepared it can lead to gluten intolerance followed by other serious health problems.

Sugar:  By 1800 annual sugar consumption in the US was 18 pounds per person, up from 4 pounds in 1700.  By 1900 annual consumption had grown to 90 pounds and today it is around 180 pounds!  For the last 30 years much of this intake has been in the form of high fructose corn syrup.  Is it any wonder that we have an obesity epidemic with all its associated health problems?

Meat and Poultry and Eggs:  During the second half of the 20th century the production of most of our beef, pork, poultry and eggs became concentrated in large concentrated animal feeding operations (CAFOs).  Here the animals live in inhumanely crowded conditions and are fed an unnatural diet of grain (GMO corn and soy); are given antibiotics to keep them from getting sick in crowded conditions; are fed growth hormones and antibiotics to speed their growth, and most spend their entire lives indoors.  Prior to that time most animals were raised on family farms and consumed their natural diets—grass for cattle, everything for pigs, and grain, grass and insects for chickens.  They were out in the open receiving natural sunlight.  This change in farming practices has resulted in profound changes in the nutrient quality of the meat and eggs and consequently in our health.

Dairy Products:  Pasteurization of milk came in to widespread use after the discovery of the process in 1864.  It was necessary as people congregated in cities during the industrial revolution and at the same time dairies near these cities produced milk under filthy conditions, and tests were not available to detect pathogenic bacteria.  Prior to that time raw milk was consumed from family or neighbor-owned cows.  Today, with the advent of modern milking equipment and adequate testing for pathogens many people are returning to raw milk for its health benefits.  Raw milk is a living food with all its enzymes intact, meaning that it is better digested and used than pasteurized milk.

The concept of whole foods applies particularly to milk.  Whole raw milk is an excellent food.  Skim, low fat, and homogenized milk, low fat yogurt with lots of additives and sugar, low or non-fat ice cream, etc. are recent introductions to our food supply and track very closely with our current epidemics of obesity and diabetes.

Fats and Oils:  The change from consuming natural fats (butter, lard, beef tallow) to vegetable oils (corn, soy, canola) and their hydrogenated forms (margarine, shortening) happened gradually from about 1900 on.  Price was a factor—the vegetable oils are much cheaper. At the same time incidence of heart disease was rising and continues to be the #1 cause of death in the US.

Fruits and Vegetables:  Since the advent of industrial agriculture in the mid 19th century with the discovery that nitrogen, phosphorus and potassium are necessary for plant growth, and especially since WWII with the advent of synthetic pesticides, produce has been grown on undermineralized soils and bred for keeping and shipping qualities rather than nutrition and taste. It is no wonder that people do not consume the recommended amounts!

Organic farming, or a return to traditional ways, is gaining ground and organic produce has been shown in some studies to contain more nutrients than conventionally grown produce, especially if it is bought and consumed locally.  It also tastes better and may lead to higher consumption and thus better health, but it is only about 3% percent of the market.

Soy:  Contrary to popular opinion, soy has not been a staple food in Asian countries except in its fermented forms (soy sauce, natto, miso, tempeh).  And it has been consumed in very small quantities, more as a condiment.  Fermentation neutralizes toxins naturally found in soy.  Cooking does not.  Modern soy foods (soy milk, unfermented tofu, soy flour, texturized vegetable protein, etc.) contain antinutrients (phytates, trypsin inhibitors), as well as estrogen analogs.  Some early puberty (girls), retarded growth of genitals (boys) and depression of thyroid function are being associated with high soy consumption.