Set Point and Metabolic Downregulation
From the above – Jason Phillips @10:00
Say your set point is burning 2500 calories per day. And all of a sudden you are consuming 1500 calories [a day] — because that is a common dietary prescription. What do you think your body is actually doing in this area? It’s downregulating its metabolic response.
Jason goes on
As your consuming less and less calories you are convincing your body to be a fat storage machine not a fat burning machine.
From the article (Metabolic downregulation doesn’t explain dieters’ weight regain):
The theory that adaptive changes in the resting metabolic rate (RMR) of weight-reduced persons predispose them to regain weight is challenged by new evidence published in The American Journal of Clinical Nutrition. The set point theory holds that the body has a homeostatic feedback system which causes an adaptation in the energy efficiency of metabolic processes during calorie restriction, with the aim of maintaining fixed fat stores and body weight. In a study of 24 overweight postmenopausal women, Weinsier et al. found no significant differences in RMR between the subjects once they had stabilized after weight loss and a control group of never-overweight women. Four years after their weight loss, the overweight subjects had regained an average of 10.9 kg, and their RMR’s were not significantly different than they had been previously.
Jason Phillips quotes Lyle McDonald for this theory but he is misunderstanding Lyle’s view. Lyle disagrees with this “metabolic damage/set-point theory” in his article (Another Look at Metabolic Damage, April 17, 2014):
Because in no study that i have ever seen or ever been aware of has the drop in metabolic rate (whether due to the drop in weight or adaptive component) EVER exceeded the actual deficit whether in men or women. Fine, yes, it may offset things, it may slow fat loss (i.e. if you set up a 30% caloric deficit and metabolic rate drops by 20%, your deficit is only 10% so fat loss is a lot slower than expected or predicted) but it has never been sufficient to either stop fat loss completely (or, even to address the even stupider claim being made about this, to cause actual fat gain).
Also from the same article, Lyle wrote:
Perhaps the classic study in this regard was the oft-quoted (and oft- misunderstood) Minnesota Semi-Starvation Study. In it, a dozen or so war objectors got to avoid going to war and arguably got into something worse. That is, researchers wanted to study long- term starvation as might occur during war or famine or being held in a prisoner camp.
Specifically the men were put on 50% of their maintenance calories, subject to forced daily activity (walking, NO weight training) and basically had their lives controlled and managed for 6 months. And in various sub-analyses, it was found that, by the end of the study the total drop in metabolic rate was nearly 40%. That is, of the original 50% deficit in calories, 80% of it had been offset. Of that 40%, a full 25% was simply due to the reduced bodyweight. Again, lighter bodies burn less calories and there’s no getting around it. But that also means that the adaptive component of metabolic rate reduction was only 15%. Which is about the largest drop ever measured (most studies measure less).
Why Do I Care?
My problem with this notion of metabolic damage is very personal. I didn’t diet for over ten years believing that it would mess up my metabolism even worse. And I was 250-280 lbs in that time-frame. I was wrong. I had plenty of body fat to diet from and was at no risk of any metabolic damage. Nobody with 100 lbs of body fat is at any actual risk of metabolic damage.
At the Extremes
Angus Barbieri is the most extreme evidence of the point. He was 450+ lbs and went on a water only fast for 282 days. He lost weight down to 185 lbs and five years later his weight was just 195 lbs.
The Key is Getting to the “Ideal” Weight
The key for Angus and others is reaching the “ideal” body weight. Often people diet and regain over and over again through their lives. But they never reach their ideal body weight. They might drop from 250 to 220 and they feel great about it. They then regain the weight and probably some more weight – ever ratcheting up.