Secret behind why you can regain weight AFTER you’ve lost it uncovered by scientists

It can be a vicious cycle for those on a diet – you manage to lose some weight only to put it straight back on again.

Now researchers have discovered why some people may end up stuck in this never-ending rut.

People who are obese release less of the ‘reward’ chemical dopamine when they eat, a new study suggests.

At the same time their brains are less able to register that food is in the stomach – and this effect lasts even after being on a diet, scientists found.

The amount and type of food people eat is regulated by complex signals sent between the brain and the gut, as well as nutritional signals in the blood.

This network triggers feelings of hunger and satiation, regulates food intake as well as the motivation to look for food.

A team led by Amsterdam University infused nutrients including carbohydrates and fats into the stomachs of 30 people who were a healthy weight and 30 obese individuals.

Their brain activity was measured as well as how much dopamine was released.

Results, published in the journal Nature Metabolism, revealed the brain activity and dopamine release was severely blunted in obese participants compared to those who had a healthy body weight.

They also discovered a 12-week diet, which led to 10 per cent weight loss in the obese participants, was not enough to restore these brain responses to normal.

Professor Mireille Serlie, lead researcher from Amsterdam University, said: ‘Our findings suggest that long-lasting brain adaptations occur in individuals with obesity, which could affect eating behaviour.

‘There is reduced capacity of the brain to register that food is in the stomach which might lead to overeating.

‘We found that those with obesity released less dopamine in an area of the brain important for the motivational aspect of food intake compared to people with a healthy body weight.

‘The fact that these responses in the brain are not restored after weight loss may explain why most people regain weight after initially successful weight loss.’