Is obesity caused by a lack of will power in terms of limiting food consumption and increasing activity levels, or is it a defect in fat metabolism causing the nutrients consumed to be converted into fat as opposed to being used for energy, resulting in cell starvation and lethargy?
Personally, I don't believe in the law of thermodynamics when it comes to human metabolism and obesity. I don't believe that a calorie is a calorie, and that to lose fat one has to eat fewer calories than one burns, and to gain weight one must eat more calories than one burns. I am a rather small person, yet I eat like a horse. Many people have asked me where I put it, and if I have a hollow leg. I eat much more than many who are three times my size, yet I remain quite slim, whereas others only have to be in the same room as a pastry and it winds up on their hips. I don't do a crazy amount of physical activity either. I see many people in the gym that are trying to lose weight who exercise a lot more than I do, and the weight does not move much. My observations do not a scientific study make, but there is a fair bit of science, albeit mostly ignored, that does make a strong case for a problem with metabolism being the root cause of obesity as opposed to slovenly behaviour.
Much of the obesity research was done in Germany prior to World War 2, and large strides were made in delineating the metabolic problems that led to obesity. Perhaps because the research was done in the German language rather than English or because the war was essentially against Germany, somehow after the war, that important research was not taken up again, and the behavioural view of obesity took hold. Even today, physicians commonly refer their obese patients to psychiatrists, psychologists and/or dietitians who try and get to the bottom of why they can't control their eating, put them on low fat, low calorie diets, and tell them to move more. Very little weight is lost on these plans - losing 8 to 10 pounds if one weighs 300+ does not resolve the problem. Suggesting to someone that it is their fault that they are overweight, and they only need to pick up their socks, stop eating so much and exercise more just adds guilt and frustration. It makes sense to assume that most obese people have already tried to lose weight through calorie restriction. Those people will tell you that it is NOT that easy. I think that suggesting that obesity is a psychological problem and is simply a matter of will power, does not make sense.
Does controlling calories actually lead to weight loss? Well, no. Calorie restriction rarely leads to substantial weight loss in the obese. If we look at rat studies where it is easy to control the number of calories consumed, we see that calories consumed does not determine whether or not the rat becomes obese. Jean Mayer noticed in the 1950s, that a genetically obese kind of mouse would put on fat weight no matter how few calories they were given. Even when semi-starved, the metabolism of the mice would result in organ and muscle wasting rather than a reduction in the fatty tissue. In 1981, Greenwood found the same thing using Zucker rats, a genetically obese kind of rat. She actually found that the Zucker rats that were calorie restricted from birth wound up fatter than those who could eat what they wanted, leading one to wonder if calorie restriction causes obesity.
It seems that it is the type of calories that is more important than the number of calories. Blake Donaldson who worked with Robert Halsey, one of the founding four members of the American Heart Association, started working with obese patients in 1919. He abandoned semi-starvation diets after a year of trying in favour of a higher calorie, carbohydrate restricted diet of which fatty meat was the staple. His patients tended to lose 2-3 pounds a week without feeling hungry. He successfully treated obese patients on this diet for 40 years. Alfred Pennington also started out by trying low-calorie diets that restricted fats and carbs, but then found success when he tested Donaldson's higher calorie meat diet (over 3000 calories a day, but only 80 calories from carbohydrate a meal, and none from starch or sugar). Pennington's work was published in the New England Journal of Medicine in 1950. The low calorie advocates pushed back, suggesting that these diets were monotonous and therefore actually were low calorie, and that they were unhealthy due to the larger amount of fat being consumed. This was around the time that Ancel Keys was pushing his "fat causes heart disease" theory. John Thorpe suggested in 1957 that semi-starvation diets were unhealthy because they resulted in malnourishment, causing the body to reallocate its resources resulting in muscle and bone wasting, rather than targeting only fat loss. Thorpe also successfully prescribed Pennington's and Donaldson's diet to his obese patients. Other clinicians that had success with the carbohydrate-restricted diet with their obese patients include Margaret Ohlson, Charlotte Young (J. Am. Dietetic Ass.), Hilde Bruch, William Leith (McGill), George Blackburn (MIT and Harvard Med. School), Russell Wilder (Mayo Clinic), Heinrich Kasper & Udo Rabast (U. of Wurzburg), Edwin Astwood (Tufts U.), Willard Krehl (U of Iowa), Weldon Walker (Walter Reed Army Med Center), John LaRosa, (State U.), Robert Kemp (Walton Hospital Liverpool), and of course Robert Atkins, of Dr. Atkins' Diet Revolution fame. Clinicians tend not to be scientists, and clinical success does not usually make its way into medical journals. In 2003 a review study was done, published in JAMA, which concluded that the scientific data was "insufficient to recommend or condemn the use of these diets", because no long term controlled trials have been done to verify the safety of low carb diets. However, the lower carb diets did result in far greater weight loss - 37 pounds compared to 4 pounds when carbs were not restricted.
Many of you may object to me bringing up research that is almost a century old in dealing with this topic, but I think that sometimes lines of research get abandoned or forgotten simply because another idea becomes all the rage, and not because the first idea has no merit. And dismissing out of hand the experience of clinicians that have successfully treated thousands of obesity patients because their method has not yet been "proven" in the medical literature seems premature. I also think that because something is old does not mean it is irrelevant. After all, the theory of relativity is an old idea. Does that idea no longer have any credence simply because it is old? Thankfully, probably due to the Atkins craze, scientific research has resumed comparing low carbohydrate diets to low calorie / low fat diets, and most of the randomized controlled trials not only are showing more weight loss, but also better lipid profiles on the carbohydrate-restricted diets. I think it is time to realize that low-calorie diets don't seem to work, and to research more thoroughly why higher calorie, carbohydrate-restricted diets do seem to work. And by accepting that fact, we are also accepting the fact that the calories in vs. calories out hypothesis needs to be discarded with respect to weight gain and weight loss. I think that obesity is a disorder of fat accumulation as opposed to a disease of overeating (too many calories). Next week we will explore the metabolic hypothesis as the cause of obesity.
Although I have been coming to these conclusions based on my own studies over the last year, the recent book by Gary Taubes, Good Calories, Bad Calories lays out the research so vividly, and has been invaluable in clarifying various ideas, and in pointing me to different kinds of research that I had not considered before. I HIGHLY recommend this book if you are interested in the topics of diets, obesity, heart disease and diabetes. I look forward to your comments on my blog.
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Taubes, Gary Good Calories, Bad Calories, Challenging the Conventional Wisdom on Diet, Weight Control, and Disease Alfred A. Knopf, New York, 2007.
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Copyright 2008 Vreni Gurd
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