By Tom, on August 17th, 2010
Most of the research for this article was done by Gary Taubes in his unbiased look at the science behind our current beliefs on cholesterol, fat, and calories Good Calories, Bad Calories (if you buy through this amazon link we will get a share of the sale). The conclusions made are my own.
The USDA has taken to heart the idea that calorie restriction is the way to conquer the obesity epidemic. They have taken this position because a misguided medical research community believes that weight gain is caused by a lack of willpower on the part of the American people and the belief that the body sees all calories exactly the same. These beliefs are a result of a medical community which, because of our complex human body, requires specialization. In this system the most prominent and outspoken get their research accepted as gospel whether it is based on good science or not. Other specialties then base their beliefs on that research and use it to make decisions in their own fields. These most prominent in the medical community decided in the 1950s to discard the obesity research of the first half of the century, because it was performed by the Germans. In its place they envisioned a system in which the obese are lazy and gluttonous, the body is bound by the first law of thermodynamics (i.e. that l calories entering the body must equal calories burned, stored, or leaving the body in another form), and, while diabetes is a disease caused by insulin resistance, obesity is psychological despite their metabolic similarities.
WHAT IS A CALORIE RESTRICTED DIET?
Calorie restriction as a diet is simply consuming fewer calories, exercising more, or both. It is also known as a semi-starvation diet, but no one would want to do a diet with that name. The premise is that the body sees all calories the same. Therefore, if you eat less, your body won’t have excess calories to store, if you exercise more your body will use the calories that were going to be stored.
The USDA recommends this diet in the 6th edition of Dietary Guidelines for Americans. This recommendation is based mostly on an article in a special 2003 edition of Science that described the “energy gap:” an average excess of calories that society is eating. This energy gap could be eliminated by eating 15% less or exercising more. They also believe that since a calorie is a calorie, foods high in fat should be avoided due to their supposed link to heart-disease. This in turn causes a diet to be high in carbohydrates. In previous articles I covered the effects of high carbohydrate diets and the harm they may cause in both the cardiovascular system and the rest of the body.
Proponents of calorie restricted diets believe that hunger can be conquered; that it is just a psychological condition that can be overruled by superior willpower. This is why there are support groups for the obese. They think that the obese who don’t lose weight are weak and probably liars, since they are obviously cheating. This is not the case. Hunger is not psychological, it is physiological. Hunger is your body telling you it is malnourished. It is a demand that is almost impossible to refuse. Even when hunger is overcome, calorie-restricted diets still fail.
WHY CALORIE RESTRICTED DIETS FAIL
Calorie restriction will cause a law of nature to come into effect: Newton’s third law. That’s the one about an equal and opposite reaction. Our bodies react to general calorie restriction with a reduction of energy expenditure and a halt on release of fat from adipose tissue (the tissue where fat is stored). People on severely calorie restricted diets will become lethargic and endlessly hungry. It almost always results in the dieter cheating on the diet purely because they can’t help it.
In an earlier post, I mentioned Ancel Keys’ semi-starvation study. In this study he put World War II conscientious objectors on a semi-starvation diet that simulated the diet the troops would face in famine stricken Europe. It consisted of about 1500 calories, mostly from carbohydrates. All subjects became lethargic; some became severely depressed, even psychotic. They lost about a quarter of their fat stores but, upon release from the study their bodies recuperated their entire previous fat store plus on average 5% more fat.
This increase of weight is very common after going off a calorie restricted diet. It is part of homeostasis which is controlled by our metabolism. One hormone in particular controls metabolism: Insulin. While all the other hormones spur us to burn calories, insulin wants to store fat.
The function of insulin is to take excess nutrients (glucose) and store them for future use. While insulin is in the bloodstream it prevents fat from being released from the adipose tissue (the tissue where the fat is stored). The problem is that when too much insulin is in our system we will be hungry and when there is too much glucose in our system our pancreas will secrete more insulin. Furthermore, in this day of readily available highly refined carbohydrate, which is easily converted into glucose, our bodies have so much glucose and insulin that they have become insulin resistant. It then takes more insulin to store the same amount of glucose. Fat burning is halted by insulin and insulin seems to be constantly in the system of the obese. The solution to this cycle is obvious if you read my previous articles, eat less sugar and carbohydrates.
THE SOLUTION: CARBOHYDRATE RESTRICTION
Low-Carb diets are blasted by most of the medical community as fad diets. They argue that although these diets can be effective, they are unsafe. This assertion is also based on flawed science. This argument is that carbohydrate restriction doesn’t provide the vitamins and nutrients the body needs and that the brain requires glucose to function properly.
Low-carb diets work by preventing the insulin cycle that I mentioned before. Insulin is always released immediately when you eat and then again after the pancreas notices there is excess glucose in the bloodstream. Low-carb diets don’t allow your blood sugar to be elevated; therefore they prevent the second wave of insulin. Since insulin is the hormone that prevents fat from being released as energy, low carb diets promote fat-loss by preventing insulin. In this same way they also may prevent diabetes and other metabolic disorders, as those are caused by insulin resistance.
The argument that this diet does not provide the vitamins we need, especially vitamin C, which is only available in high quantities in high carbohydrate fruits, has an interesting twist. When sailors spent months at sea and didn’t get fruits and vegetables they suffered horrible deficiency diseases, but only when they ate typical naval diets. The Scottish Naval surgeon James Lind is the man who discovered that eating citrus would prevent scurvy. The men that he studied were eating typical sailor high-carb diets “of water gruel sweetened with sugar in the morning, fresh mutton broth, light puddings, boiled biscuit with sugar, barley and raisins, rice and currants.”
Vitamin deficiency is non-existent in populations that eat nothing but meat, as is the case of the Inuit. They eat primarily caribou meat, but supplement their diets with other meat and eggs. When times are dire they may eat the roots of the knotweed plant, but believe vegetables and fruit are “not human food.” They are in perfect health and very active. How is this possible?
Animal food contains all of the essential amino acids and twelve of thirteen essential vitamins in their necessary quantities. Only vitamin C is low, however it seems we need less vitamin C when glucose is low. Glucose and vitamin C are similar in configuration and vitamin C is also delivered to the cells by insulin. When blood sugar is elevated vitamin C delivery is inhibited. So, in fact, what causes scurvy is not caused by lack of fruit, but the presence of carbohydrate which causes elevated glucose levels.
It is also argued that the brain requires glucose to function properly. This can be dismissed fairly quickly. When the liver detects low glucose levels it starts producing ketone bodies which replace glucose as fuel for the brain. These ketone bodies can supply up to 75% the central nervous system’s energy. If necessary, the body can make its own glucose from amino acids and glycerol, a byproduct of the breakdown of triglycerides.
Entering ketosis is actually a daily occurrence for our bodies. It is the reason that we are not commonly awakened from sleep by hunger. Our bodies make the switch to ketone bodies while we sleep. The presence of ketone bodies actually suppresses hunger, raising the question: does the brain actually prefer ketone bodies? When the body feels like it needs more nutrition, it asks by making you hungry. When it has ketone-bodies, resulting from a lack of carbohydrate, it suppresses hunger.
It seems from these examples that our bodies actually prefer a diet high in protein and fat; and that our bodies only like to store carbohydrate fuel. This would explain why our national level of obesity has only increased since the denunciation of high-fat diets and promotion of high-carb low-calorie diets by the medical community and our government. If we return to the diet of our ancestors, and the Inuit, we will be healthier and leaner.
Further Reading on this topic: