As I talked about in my last post, the set-point, starvation-response, and metabolic-adaptation theories have kept changing over the years as their advocates attempt to maintain a viable theory. The Truth? Are there physiological changes associated with energy restriction? Yes. Do they prevent weight loss, or maintenance of weight loss? No.
The biggest danger with these theories is their application by the public (and some professionals). If you believe you have no control over your weight that will be a self-fulfilling prophesy.
That's why one could argue that these notions have done as much to promote the obesity epidemic as the cultural, lifestyle, and environmental challenges that also clearly promote it.
Why are there conflicting viewpoints about the viability of set-point theory?
Humans can't help but attempt explanation for things we observe happen. Set-point theory was an attempt to explain the observation that a lot of people fail at weight-loss-maintenance. When scientifically tested however, the data did not validate the hypothesis--that the body adjusts its RMR to prevent weight loss or reestablish a previous higher weight. In fact RMRs do normalize after losing weight. There are also plenty of examples of folks who do maintain significant weight losses, like me (40-lbs for over 20-years) and several thousand people followed in the National Weight Control Registry.[i] Successful maintainers are another fly in the ointment to set-point theory.
If we really boil it down, some of the argument is just over semantics and definitions. Beyond that, however, there are even deeper fundamental differences in viewpoints:
Set-point camp: They seem to believe that, a) Body weight is outside a person's realm of control; b) Dieting leads to eating disorders; c) Psychological issues underlie obesity. However, The National Institutes of Health finds that dieting doesn't promote eating disorders.[ii] And, several studies looking for a link between psychological variables and obesity found no correlation.[iii],[iv],[v] I do think the set-point camp's hearts are in the right place. They do want to protect people from the dieting industry, and weight loss supplement manufacturers, which prey on folks who are desperate for help.
Behavioral/Environmental camp: They believe that, given an individual's genetic predisposition, the rest of the equation is lifestyle and environment which are within one's personal realm of control. Is it easy to lose or maintain weight loss in modern society? No, but it is doable, and it requires permanent lifestyle changes. We actually do know what folks need to do to be successful.[vi]
Obviously, I'm in the behavioral/environmental camp. The original proposed mechanism for set-point (an increase in metabolic efficiency) has been debunked. End of story (see item 2 below).
My thoughts regarding obesity genes: Are we genetically mutating at a rate that explains the jump in BMIs over the past 30 or 40-years? No, no one suggests that.
My thoughts regarding leptin, and ghrelin: interesting, I recall hearing theorizing that leptin receptors were "broken" in subjects with obesity, because the subjects didn't seem to be affected by high levels of blood leptin (which normally tells the brain, "you are not hungry"). I know big pharma is all over it, and it's in their financial interest to create the hope that they will come up with a miracle. My advice: don't hold your breath. There are no magic bullets.
The final thing that bothers me about set-pointers is that they seem to pretend that humans don't have a brain, and that they don't make hundreds of choices about eating and exercising every day/week. What do you think is overriding/ignorring the leptin? We have disassociated hunger and eating in our modern culture. We eat because it's there, because it's time, because other people are, etc. etc. Yet set-pointers seem to want to pretend that some external force controls everything... last time I checked, I'm the one that chooses what goes in my grocery cart!
My heart—and the heart of all of us in the behavioral/environmental camp—is in the right place too. It's not my decision whether someone chooses to try to lose weight or not. If they do choose, however, I will not tell them, "Don't try it's too hard.” I certainly won't tell them, “Don't try, it's hopeless, it’s out of your control.” Nope. I'll tell them what's possible, and what it will take. This approach, I think, is similar to what Phillip Moffitt meant when he said:
"The only true compassion is to point a person to their own liberation."
The truth is it's hard. There are a lot of problems to solve. The first step in problem-solving is acknowledging and identifying the problem. It's not good or bad; it's not right or wrong—it just is what it is.
For more information see:
1. How dieting (energy restriction) affects resting metabolic rate (RMR)
2. Set-point theory is not supported by the literature (updated 16-MAR-11)
Love to hear your thoughts!
-Dorene
[i] Klem ML, et al. A descriptive study of individuals successful at long-term maintenance of substantial weight loss. Am J Clin Nutr 1997;66:239-246.
[ii] Nat’l Taskforce Prev. Treat. Obes. Arch Int Med. 2000;160:2581-89)
[iii] Wadden TA, et al. Am J Clin Nutr 1992;56:271s-4s
[iv] Berman WH, et al. Behav Med 1993;18:167-172
[v] Wing RR, et al. Baillieres Clin Endocrinol Metab 1994;8(3):689-703
[vi] 1998 NIH Report: Clinical Guidelines on the Identification, Evaluation & Treatment of Overweight and Obesity in Adults.