The “Set Point” Theory and Obesity
The rise of obesity in all of the industrialized countries have reached an alarming number. Nearly 2/3 of the population in the United States is considered overweight, and about 1/3 of Americans over 20 are obese(1). Health practitioners and researchers are very concerned about this trend, and we all are trying to figure out how we can change the outcomes.
Theories abound as to why people are obese, and I think many of them have merit. There is one put forward by Rudolf Liebel, M.D., that seems pretty grim if he is right. It is called the “Set Point” theory.
Here is the video with Rudolf Liebel:
His premise is this: body weight, including how much muscle and how much fat the body will carry is tightly regulated, and that as soon as the individual deviates from the “set point” that the body has, it will do everything it can to get back to the original weight and fat level. They compared lean people with overweight people, and they found that the “set point” theory was the same in both groups, i.e. that if lean people gained weight, metabolic and hormonal factors would drive the lean individual to get back to his original weight as well.
One of the signaling hormones Dr. Liebel and company discovered was the hormone called Leptin that is created by the fat cells. When body fat levels are higher, Letpin levels are higher, and vice versa when body fat levels are lower. Dr Liebel noticed that when Leptin levels are lower in overweight people, they are hungrier, have a slower basal metabolic rate and tend to want to move even less so. Interestingly, the researchers noted about a 20% reduction in energy expenditure. So, for example, the person who is dieting but who may be at the weight as someone who is not dieting will need to eat 20% fewer calories than the non-dieting individual to maintain her weight.
In the documentary above, Dr. Liebel took a woman who is overweight and put her in a carefully regulated environment. She was moved into a hospital for nine months, consumed an entirely liquid diet, and had all of her physical activity controlled. The first 4 to 6 weeks they calculate how many calories are needed to maintain body weight. Once the baseline is established, Dr. Liebel then has the participant eat 800 calories a day (still liquid diet) to see how the body responds to the weight loss.
The good news is that the woman in the study lost 40 pounds over the nine months. The bad news is that, according to the researchers, she will need to eat 300 calories less a day now to maintain her weight.
What about Leptin? The researchers did inject her regularly with Leptin during the study, and she did have food cravings less often and her metabolism did improve, but at this point the researchers still do not think it is a viable strategy for weight loss. Personally, I agree because I think it is much more complex than just taking some injections for permanent fat loss.
After the study, the researchers sent the woman on her way, and they, of course gave her advice on how to manage her weight, but they also told her it will be an uphill battle. So, in effect, she will always fight food cravings, temptations and old eating patterns….and she now has to eat even less than she did before.
I don’t think this is a good plan. She is set up for failure. Could there be more to the story?
I think the set point theory is valid. After all, these researchers have studied weight metabolism for years, and it is true that some people lose weight and are able to stay leaner than others. But I have to ask the question…how is the “set point” , well, set?
I cannot rule out the role genetics play in how much fat an individual will ultimately carry, but we can tell our bodies to gain or lose fat by certain environmental stimuli. For example, we know that intense strength training will send a signal to the body to put on muscle. Moreover, we can tell the body to run longer distances by consistent bouts of long distance running. Could it be that overweight people are sending signals to get and stay fat? Is it possible that the researchers above did the same thing?
I believe the researchers did exactly that. First of all, restricting caloric intake as low as they did does tell the body that food is scarce, and that it needs to down-regulate it’s metabolism to survive. It will get more efficient at burning calories for the same amount of activity. Furthermore, the body will want to move less to save energy as well. Secondly, since it was a liquid diet, I would bet that the diet was high in carbohydrates. They did not address the macro-nutrient content given to the subject, and I suspect it was because the researchers do not believe that tracking the macro-nutrient content was important. Just the calories. The alternative hypothesis suggests that high carbohydrate diets will make it harder for the body to lose fat, and that limiting carbohydrates will shift the body into burning fat more easily and suppressing appetite with fewer calories. Thirdly, the type of exercise that they had the participant do was cardio exercise. This is typical of practitioners who think that all exercise really does is change the energy equation by burning more calories. The body will simply get more efficient at burning calories with this type of exercise, and it will down-regulate energy expenditure in a similar vein as a too low calorie diet. Moreover, adding cardio can increase appetite too. Strength training, on the other hand, will build muscle which is metabolically active and will raise the basal metabolic rate, thus burning more calories even when the person is not exercising. Additionally, strength training while keeping calories low will tell the body to keep the muscle…and lose the fat.
For all of the controlled studies that Dr. Liebel has done over the years, I get the impression that he did not take a closer look at these variables. I believe the set point theory is valid, but I also believe that the set point can be adjusted up…or down to a certain degree by manipulating them. I really do not believe it is as hopeless as Dr Liebel makes it out to be. The set point can be “re set”, but it would take a strong commitment to a productive intervention program because the body is stubborn. It needs the stimuli to be consistent for a few months before the body will adjust.
Food for thought.
1. Obesity Statistics: Worldmeters. http://www.worldometers.info/obesity/