The reason why you're likely to gain weight with more diets

People who regularly go on diets often gain weight after finishing the regime - the phenomenon is known as yo-yo dieting and is often attributed to changes in metabolism.

A study, published in the journal Nature by a group of Israeli scientists, looked at the non-genetic factors behind yo-yo deiting, concluding why it affects certain people more and how to reverse it.

The researchers fed mice in several diet plans, alternating between weight loss and weight gain diets.

Starting with high-fat portions to fatten, then slimming with light normal meals, they repeated the regime on a cycle.

Like humans, the mice gained weight compared to mice on a diet of steady calories.

Why?

Mice that bounced back with an increased weight regain actually had a lower energy expenditure than mice on steady diets but ate the same amount of food. This accounts for some of it.

Researchers think the weight gain was predominately due to gut microbes.

There were marked differences in the gut microbes of yo-yo dieting mice and steady dieting mice - including a reduction in diversity, a trait which correlates with obesity.

When they transplanted the microbes of yo-yo dieters into normal mice they saw those mice gain weight.

These microbes were found to cause weight gain due to how they digested plant fibre, a staple in the diet.

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