Researchers at the University of Washington cite the role of a complex control system in the brain that adjusts the calories our body takes in and expends, both immediately and over the long term, to achieve homeostasis and keep our “body energy status”— our weight— stable over time. Similarly to the way the body automatically regulates insulin and blood glucose until that system is overwhelmed and breaks down (leading to type 2 diabetes ), the body automatically regulates body fat until it is overwhelmed and breaks down (leading to overweight and obesity ). Another way to think of it: Much as we exhale more when we inhale more, or we urinate more when we drink more, we also burn more when we eat more and burn less when we eat less— automatically. Breaths in and breaths out, water in and water out, and calories in and calories out are matters of established human biology, not mythical metabolic math. This “burn more when we eat more” behavior explains how we’ve gained dramatically less than what would be predicted by calorie math. The “burn less when we eat less” behavior explains why studies show traditional calorie-counting approaches failing 95.4 percent of the time— and often provoking even greater rebound weight gain. When we put these two biologic behaviors together , we can see why every weight-loss study ever conducted shows that when people are given a surplus or shortage of calories, they never gain or lose the mathematically anticipated amount of fat. The body just doesn’t work that way.
