Diet, lose weight, regain weight, lose it again – and so on and so on. Yo-yo dieting is an all too common phenomenon as more and more of us try to lose weight and improve our health. However, even if we manage to succeed, most of us are not able to keep it off. Indeed, of those that do lose a significant amount, roughly eight in 10 will regain that weight within a year.
Why yo-yo dieting often fails
The very act of losing weight triggers a fight-back mechanism in the body – it sees that loss of weight as a threat. To counter the supposed threat, it sends out hunger signals to encourage eating and, at the same time, slows its metabolism so as to conserve fuel, i.e. it’s fat stores.
While this metabolic adaptation served our ancestors well during the long-ago years of feast and famine, it is not nearly as effective in today’s environment in which food is so plentiful. Rather, it actually encourages weight gain, particularly in people who are genetically predisposed to it. Repeated attempts at dieting do nothing to reduce this vulnerability.
Another reason is that restricting food increases its appeal which can lead to overeating, or even bingeing. The result, as ever, is an increase in weight – often more than was lost originally.
There’s a mental aspect to this as well. The more frequently someone goes through the gain – lose – gain – lose cycle, the less confident they will be in their ability to ever succeed. It just gets harder and harder.
What happens when it fails
What often happens is that dieters regain more fat than they originally lost. The theory behind this is that when dieting most people don’t just lose fat, they lose muscle as well due to lack of exercise. And when they lose muscle mass, their metabolic rate goes down.
When they have finished the diet, they go back to eating normally. However, because their metabolic rate is still low (and will remain so for some time), their body gains more fat than it would normally. This continues until the body has put back the muscle it lost during the diet and its metabolism has returned to normal.
A recently published study confirms the above by showing that when the body’s regular supply of food is interrupted (and it can’t differentiate between dieting and famine), it stores more fat each time a person’s eating returns to normal than it does overall when their food intake remains constant.
Yo-yo dieting is a cycle of short-term changes in eating and activity. The benefits are also short-term. It can actually be counter-productive and lead to the accumulation of more body fat than existed at the beginning of the cycle.
More dangerously, people with a body mass index at or below normal, who engage in yo-yo dieting, appear to have an increased risk of type 2 diabetes, high blood pressure and heart disease.
A much better way of going about losing weight is to make small, and thus easier to adhere to, dietary and lifestyle changes.