People who swear by a particular diet to lose weight may be fooling themselves, according to a recent study by scientists at Pennington Biomedical Research Center in Baton Rouge, Louisiana. There is no real evidence that low-carb, low-fat or high-protein diets make as big a difference as overall calorie reduction when it comes to weight loss, according to Dr. George Bray who worked on the study.
Study Finds It Makes Little Difference
Where Calories Come From
“Earlier research had found that certain diets – in particular those with very little carbohydrate – work better than others. Diet books also often guide consumers to adopt a particular type of meal plan. But there hasn’t been a consensus among scientists,” Dr. Bray said in an interview with Reuters Health (1/30/2012).
For the study, several hundred overweight and obese people were assigned in equal groups to four different diets: (1) Average protein, low fat and higher carbs; (2) high protein, low fat and higher carbs; (3) average protein, high fat and lower carbs; (4) and high protein, high fat and lower carbs. All diet styles were designed to allow for an energy deficit of about 750 calories per day.
The participants were weighed after six months and again after two years. The researchers found that, although most lost weight and managed to keep at least a few pounds off for two years, “there were no differences in weight loss or fat reductions between the diets.”
The study, which was published in the American Journal of Clinical Nutrition, also determined that stick-to-itiveness was a crucial factor for the success of any of the diet regimens – but also one of the hardest to achieve. “The major predictor for weight loss was adherence,” said Dr. Bray. “Those participants who adhered better, lost more weight than those who did not.”
While these study results should not come as a major surprise, they are not necessarily welcome news for the diet- and weight loss industry. After all, Americans spend billions of dollars annually in a highly competitive market of weight loss programs and dieting ideas. Could the ultimate solution be as simple as eating less and burning off more calories for the rest of your life?
Not quite, according to Dr. Scott Olson, a practitioner of alternative medicine and author of “Runner’s Soul.” “Using calories as a way to measure what you should be eating can only take you so far,” he says. The reason is that you are not a calorimeter, you are a living being and not some laboratory tool. Something happens when you consume carbohydrates that is different from what happens when you eat protein or fats – regardless of calories.”
Dr. Olson sees focusing exclusively on calories regardless of their source as a misguided approach because it misses out on other important issues. “Calories don’t matter as much as blood sugar, especially when you are talking about weight loss. To lose weight, yes, you need to burn more calories than you are consuming, but you also have to keep your blood sugar from spiking too high and causing your body to store that extra energy as fat,” he said.
Dr. Bray and his fellow-researchers would agree that not all diets offer the same health benefits, even if they are comparatively effective in terms of weight loss. For that matter, Dr. Bray favors the DASH diet (Dietary Approaches to Stop Hypertension), which is endorsed by the National Institute of Health (NIH).
In my own practice as a dietitian and health counselor, I have always preached that calorie restriction for weight loss must go hand in hand with high quality nutrition. That may require cutting back on portion sizes but also loading up on important nutrients. In the end, I want my clients not just to be thinner but all around healthier. And that’s why I also want to know where their calories come from.
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I couldn’t help but see your article on weight loss and thought this study needed clarification. First of all, this study, done by George Bray, did not include any low carb diet. The lowest percentage of carbohydrate in any of the diets was 35%, which is way too much to be considered useful in exploring low carb dieting. Mr. Bray is firmly entrenched in the “calories count” paradigm, and has demonstrated in all of his studies that he will not consider an alternative hypothesis.
Most importantly, please understand that the idea that “weight gain is simply a matter of eating too much” cannot be correct for a number of fairly obvious reasons. Let me offer a few.
First: There are approximately 36,000 Calories in a pound of fat. If a person’s weight is to remain stable (say, plus or minus a couple of pounds) over a period of a few years, as many people do (even overweight and obese people) then such people
must be balancing their caloric intake vs. calories burned, on average, to less than 10 Calories per day! Think about it. Nobody consciously does anything like that! No diet plan ever suggests that and neither you or I believe that such dietary control is possible. So how is it possible for anyone to maintain a constant body weight UNLESS there are automatic, internal mechanisms that “tune” the body? The answer is there are internal mechanisms for setting body weight. The question becomes “What are the mechanisms that set body weight?”
Second: Many people use the second law of thermodynamics (calories in must burned or turned into excess weight) to explain why eating too much causes people to gain weight. While it is definitely true that calories, energy, don’t just disappear, nothing about the second law explains what drives any of the three parts of the equation. “Calories in” is somehow related to hunger. Most people stop eating when they feel full. What causes people to feel full? “Calories burned” is highly variable. A large fraction of calories burned maintain body temperature and small changes in clothing and vasodilatation can greatly affect the calories needed to do this. How is that all regulated? Given the first two items, “calories left over” can be large or small, positive or negative, and the second law says nothing about how much it might be. Gary Taubes uses the wonderful analogy: observing a restaurant full of people says nothing about why it is full. Maybe it’s slow service, maybe it is very popular, maybe it is the only restaurant in town. Saying it is full because more people have entered than have left, while definitely true, is not a meaningful explanation for why it is full.
Third: Adipose tissue is not an uncontrolled recipient of excess calories any more than, say skin or muscle or any other tissue are uncontrolled recipients. Adipose tissue responds to hormones, primarily insulin, and extracts fuel from the
bloodstream in accord with the level of insulin in the bloodstream. It is precisely because adipose tissue extracts fuel that people with excess adipose tissue (fat people) appear to eat too much. It is backward thinking to believe a fat person eats too much and therefore gets fat; rather, a fat person’s adipose tissue removes lots of fuel to make fat cells bigger. In order to have fuel left over for other metabolic functions a fat person needs to eat more. The real question is why does adipose tissue extract so much fuel? Answer, primarily, is too much insulin from eating too many carbohydrates.
Have you seen the recent physician training photo in the NEJM? (Go to garytaubes.com) It shows Insulin Lipohypertrophy. The photo shows the front of a normal weight male with two grapefruit sized fat nodules on either side of his navel. The diagnosis is repeated injections of insulin at those two locations. Locally high levels of insulin, over time, told the fat tissue in those areas to
grow.
If you’ve read this far, thank you. It is important for people to start getting the fat story right. The implications for diabetes, cardiovascular disease and probably cancer and Alzheimer’s are enormous.
I, and some of my friends, have had the same failures using calorie control for decades. Then, with the insight of insulin, I quit eating carbs seven years ago and almost immediately weight became a non-issue. 35 lbs. fell off over the next 18 months without ever restricting calories once. I eat as much as I want, as often as I want, and am confident that my 23.7 BMI is not going to go up as long as I don’t eat carbs.