Dr Michael Mosley explains why 'starvation mode' is a myth

Dr Michael Mosley has said that fasting does not cause people to go into ‘starvation mode’ and so stop losing weight. Describing it as a diet ‘myth’ the weight loss expert claimed that multiple studies had shown that losing weight fast doesn’t mean you will regain it.

He said: “Have you heard of starvation mode? The idea is that if you lose weight particularly rapidly, then your body goes crazy and you eat loads of junk food and you put all that weight on again.

“Now this is a myth. It’s based on a study, which was performed shortly after the Second World War. It was actually about low protein rather than low calories as such. Nonetheless, it has hung around in the public consciousness ever since. Study after study has consistently shown the rate at which you lose weight has no impact on whether you regain it.”

Dr Mosley is known for his eating plans the 5:2 and Fast 800 diets which both involve periods of fasting and low calorie intake. Refuting suggestions that fasting and The Fast 800 Programme could force your body into starvation mode, he said in a post: “The opposite is true. Studies have revealed that some forms of fasting can actually boost the metabolism due to an increase in blood levels of norepinephrine as a result of a decrease in serum glucose, which stimulates your metabolism and breaks down body fat cells.”

Writing on his website Dr Mosley previously addressed this theory. "One of the most popular dieting myths is ‘starvation mode’, the claim that if you stop eating your metabolic rate immediately slows down as your body tries to conserve your fat stores." said the creator of the 5:2 and Fast 800 diets.

However, he says that there simply isn't the evidence to back this up. Dr Mosley said: "In a recent experiment, researchers took 11 healthy volunteers and asked them to stay in a metabolic chamber (a room where they precisely measure your metabolic rate) living on nothing but water. By day 3 their metabolic rates had risen by 14%. This was probably due to a rise in a hormone called noradrenaline, which is known to burn fat. If they had continued then, I’m sure, the volunteers’ metabolic rates would eventually have fallen, not least because they would have begun to lose significant amounts of weight. But, in the short term, there is no evidence that starvation mode is anything other than a myth."

Prime Minister Rishi Sunak recently revealed he does intermittent fasting as part of a “balanced lifestyle”. Describing it as an “important discipline”, Sunak typically doesn’t eat on Monday, which he says helps him combat his “weakness for sugary things” – apparently he loves Coca-Cola.

Instead of just focusing on what you eat, intermittent fasting encourages people to think about when you eat. The idea is, you only eat during a specific time period, the theory being that this gives your body a break from digesting food.

Some people claim that intermittent fasting mimics the traditional eating patterns of our ancestors, who would have to fast because of lack of food availability until they had hunted or foraged for it. It’s recommended to replenish the body with enough of the right nutrients whenever the fast is over.