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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.

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