Yo-Yo Effect: That’s Why Eating Too Little Makes You Fat!

Short lightning diet? Better not – because it often has the exact opposite effect of what you want. The problem: the basal metabolic rate decreases.

The yo-yo effect is hated. Maintained a proper diet, lost a few kilos – goal achieved. Then you eat normally again and the bacon is back in no time at all. The basal metabolic rate of our body is to blame for this.

Even if we don’t exercise, but just lounge around on the couch, our body uses energy. Simplified, that’s 25 kcal per kilo of body weight per day. Very simplified, mind you, because a large number of factors play a role. Last but not least, gender, stature and age. If you weren’t moving and consuming exactly that amount of energy, you wouldn’t gain or lose weight either

Less food = lower basal metabolic rate

If you eat less food on a diet, the body reacts and reduces the basal metabolic rate. This happens, among other things, through muscle breakdown, but also through better efficiency. From an evolutionary point of view, this makes sense: because in the history of mankind there have always been phases in which there was not so much to eat. Even if it was only the next cold winter. A lower basal metabolic rate means that the body can cope with less food – it gets used to it, so to speak. This is why you lose weight the fastest when you start a diet.

How far the basal metabolic rate decreases cannot be answered in general terms. Textbooks give figures between 16% and 40%.

The basal metabolic rate – an explanation for the yo-yo effect?

If you now end your diet and eat normally again, the process is reversed. The body now receives more energy than it actually needs with its reduced basal metabolic rate. Great for building up reserves in the form of fat. The basal metabolic rate also increases again – but by then the lost weight may have been built up again.

Whether the change in the basal metabolic rate is the only factor in the yo-yo effect cannot yet be said with certainty. Neurological effects of the diet on our feeling of appetite could also play a role.