Why can’t you lose weight and keep it off?

Less than 1% of people who lose a large amount of weight keep it off for more than 5 years. Sustained major weight loss is not just rare without surgery, but biologically very difficult to achieve. There are numerous mechanisms in our bodies designed to prevent weight loss. This is a very important and valuable feature, normally.

Consider the Hunter-Gatherers, days when hunting for food only resulted in a good catch once a week once a month and hardly ever during winter. If we were not able to hold on to our weight when we had no food we might not be strong enough to catch the food the next time around. And when we caught a meal we would go into storage mode to maximize the amount of energy we stored, just in case…We needed to be good at holding on to our weight. But now we have cows and farms and cafes and so we can eat more easily. But, of course, we still have these hormones etc, but no longer the infrequency of food.

It is important for survival to be able to hold on to our weight.

If you have a weight problem and try to lose weight, we can assume that your weight holding mechanisms are effective, perhaps too effective. The body detects a diet as a possible threat of a famine and goes into weight loss prevention mode, just in case there is no food for a while.

Dieting makes the body hold on to fat.

A diet stimulates weight maintenance mechanisms. The body is desperate to prevent weight loss. And then you have a little bit to eat, and the body stays in storage mode, thinking it might still be under threat of no food.

So it is basically very difficult to outsmart this system every day, to beat what is essentially a very complex and sophisticated system.

What about exercise?

There are only poor mechanisms in the body to prevent weight loss with increased exertion. So you should be able to increase you exertion and lose weight. However, all studies on exercise and weight loss in the obese show no sustained weight loss form exercise alone. Which is a bit depressing. But why not? Why does exercise not work in practice?

Exercise alone does not lose weight.

There are numerous possible answers, but the bottom line is that you can’t just exercise to lose weight and keep it off. Exercise and controlled calorie intake is another story. Exercise increases the weight loss of somebody with a calorie-controlled diet. So why is this? It is the calorie intake that is the important part, because of the mechanisms discussed above. And the body is not very good at preventing weight loss from exercise, and so the two work in concert.

So why can’t you lose weight and keep it off.

“Dieting” makes the body hold on to your weight. And yet, exercise only helps if you are dieting. This is a “catch 22”.