Mozzarella peppers casserole with juicy chicken bits
The conventional approach to obesity considers weight control as a matter of accounting — too many calories into the body, not enough calories out. The solution: count calories, eat less and move more. As long as you have a negative “energy balance,” you’ll eventually solve the problem.
Sounds simple. The problem is, calorie restriction is devilishly difficult for most people to sustain over the long term, because the body fights back when it’s deprived of calories. Decades of research shows that, as people lose weight, their hunger inevitably increases and their metabolism slows down.
The more weight you lose, the harder it is to burn off those extra calories, even as hunger and cravings for extra calories keep rising. This isn’t a matter of will power. In the battle between mind and metabolism, metabolism wins. According to nationally-representative data, fewer than 1 in 5 people with overweight or obesity have ever lost just 10% of their weight, for just 1 year.
We each have a sort of set-point, a weight that our body seems to want to remain — it’s lighter for some people, heavier for others, and determined in part by our genes. Some people can eat whatever they want and stay thin. Others seem to gain a few pounds by simply walking past a bakery. For both groups, attempts to either lose or gain significant amounts of weight run into biological resistance.
But if our biology controls body weight, why does the average person in the US weigh 25 or 30 pounds more today than 40 years ago? Our genes haven’t changed. What’s pushing our body weight set-point up, year after year? The conventional “energy balance” view of obesity offers no compelling explanation.
After all, humans have lived for long periods of time with an abundance of food — such as from the end of World War II until the 1970s in the US, the 1980s in Europe, and the 1990s in Japan — without population-wide weight gain. Something is causing the body of a person today to fight harder to maintain a lower weight than in the past.
Do We Have it Backwards?
There’s another theory of obesity called the Carbohydrate-Insulin Model (CIM), which argues that we’ve had it backwards all along: Overeating doesn’t cause weight gain, at least not over the long term; the process of gaining weight is what causes us to overeat.
Think of a teenage boy. Eating a lot doesn’t make him grow; his rapid growth makes him hungry and and so he eats a lot. (Of course, adults won’t grow taller no matter how much they eat.)
According to the CIM (see Figure 1), processed, high-“glycemic load”carbohydrates — mainly refined grains, potato products and added sugar — that flooded the food supply during the low-fat diet craze of the last 40 years have raised insulin levels, forcing people’s fat cells into calorie storage overdrive. Our rapidly growing fat cells take up too many calories, leaving too few for the rest of the body. That’s why we get hungry. And that’s why our metabolism slows down if we force ourselves to eat less.