One of the persistent myths in the fat industry is that the failure of someone to maintain weight loss is due to the individual’s sliding back into their previous slothful habits. If only they would stick with being healthy, then they wouldn’t regain all that faaattt. The truth is that the more weight you lose, the more your body will try to protect you from greater loss.
Weight loss is starvation from a metabolic perspective. That you are consciously doing it, that you are being careful and trying to balance just a small amount of calorie deficit with overall health, your body doesn’t give a rat’s ass. You are losing body mass. This is bad for survival and must be stopped.
In a study, “Adaptive thermogenisis in humans,” published by the National Institutes of Health, researchers specifically examined why weight loss has such a bad long term success rate. They came up with a simple, single sentence explanation: “The increasing prevalence of obesity and its co-morbidities reflects the interaction of genes that favor the storage of excess calories as fat with an environment that provides ad libitum availability of calorically dense foods and encourages an increasingly sedentary lifestyle.” Genetically, we’re predisposed to hold on to the weight we gain, and we’re living under conditions of food ubiquity. If you gain weight, your body wants to hold onto it.
What the study clearly identifies is that the bodies of people who diet and lose 10% or more of their body mass become measurably more efficient (20-25%) and the calories required to maintain their reduced mass is 10-15% below what someone of the same height, weight and build who has not lost that level of weight. As the authors say:
Thus, a formerly obese individual will require ~300–400 fewer calories per day to maintain the same body weight and physical activity level as a never-obese individual of the same body weight and composition. Studies of individuals successful at sustaining weight loss indicate that reduced weight maintenance requires long-term lifestyle alterations 9. The necessity for these long-term changes is consistent with the observation that the reduction in twenty four hour energy expenditure (TEE) persists in subjects who have sustained weight loss for extended periods of time (6 months – 7 years) in circumstances of enforced caloric restriction in the biosphere 2 project 13, bariatric surgery 14 and lifestyle modification 15.
This is the ugly punch line to the joke of Sisyphus’ Treadmill – the harder you work at trying to reduce your body mass, the more your body will compensate to reduce the amount of energy it needs. Read the entire NIH article for the details of how the interlocking metabolic responses to weight loss combine to keep you from losing weight, even years after you’ve achieved your goal.
This is why diets don’t work. They don’t reduce your mass and then allow you to live and eat like a “normal” person. They reduce your mass, fuck up your metabolism, and prime your body to reclaim it’s lost mass through increased metabolic efficiency. I can run one mile on less fuel than someone who has never lost significant weight.
This is also why the prescription for losing weight – to diet – is doomed to cause more of what it purports to treat. Worse, it sets up a metabolic dynamic that practically guarantees increased body mass over time, more than if the subject had not tried to lose the weight in the first place.
To go on a diet means a lifetime of perpetual under-eating and fighting hunger or a lifetime of perpetual up-down-up-down weight cycling, which has additional health risks.
Finally, this is why the misguided emphasis on weight loss above weight maintenance and improving other markers of health through physical activity is doing a double-disservice to the population. It encourages behavior that will probably make the individual’s weight increase over the long ruin and it deprecates other health interventions that may actually do greater good over time than simply losing weight, such as increasing bone strength or improving cardiovascular capacity.
But it sure makes the hucksters a lot of money and makes the food puritans feel superior.