Once you are fat, chances are you will never get slim!

Researchers claim that fat people, who lose weight either by dieting or exercising, will put it all back on again within a year.

Their study of 25,000 people provides further evidence of the prevalence of `yo-yo dieting` where slimmers get into a cycle of losing weight and regaining it, reports the Daily Mail.

The scientists, from the Medical Research Council`s National Survey of Health and Development, have concluded it is better to avoid getting fat in the first place.

Weight warning: Avoid crash diets

They followed 5,362 men and women from their birth in 1946 and 20,000 from birth in 1958, measuring their weight and blood pressure and assessing their lifestyles.

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