How DO some people stay slim without any efforts?

We all have an infuriating friend who seems to be effortlessly thin.

Now, researchers have revealed the secrets of those who never worry about their weight.

Despite their slim physique, the study found the majority of trim people rarely diet, and more than one in ten never weigh themselves.

However nearly half exercise at least five times a week, almost a tenth were vegetarian and nearly a fifth said they didn't drink alcohol. 

For breakfast, more than half eat fruit and vegetables, more than a third eat eggs and a fifth snack on nuts throughout the day.

And some 61 per cent say chicken is their favourite meat, while 65 per cent eat vegetables every day for dinner.

Almost 40 per cent of people in the 'thin' category didn't consume soft drinks, while 33 per cent said the diet option was their favourite.

The survey, from the Cornell Food and Brand Lab, surveyed 122 adults whose BMI was healthy and who reported they didn't maintain strict diets.

They compared them to another group, consisting of those struggling to maintain or lose weight. 

These people diet regularly, thought about food frequently and were highly conscious of what they ate.

Researchers found the majority (43 per cent) of mindlessly thin people were more than 41 years old, and 80 per cent were female.

Their average weight was 136lb (9st 10lbs or 62kg), and their average height 5"6.

The average BMI was 21.7, which is classed as healthy.

A BMI score below 18.5 is considered underweight; a score of 18.5 to 25 is healthy; 25 to 30 is considered overweight and more than 30 is classified as obese.

Despite their healthy measurements, the poll found 74 per cent rarely dieted, while 48 per cent didn't diet at all.

Half weighed themselves weekly, while 29 per cent never stepped on to the scales.

In terms of exercise, 42 per cent did some physical activity five to seven days a week - and only 10 per cent said they didn’t exercise at all. 

Dr Brian Wansink, director of the Cornell Food and Brand Lab and author of Slim by Design, said: 'We wanted to see what health behaviors differed between those struggling to lose or maintain weight and the mindlessly slim.

'We wanted to find the small or simple behaviors that might have a big impact.'

He found thin people's strategies differed from conventional weight loss advice.

They included eating high-quality foods, cooking at home, and listening to inner cues in order to stay slim.  

A noticeable difference was they didn't report feeling as guilty as the other group about overeating.

During the study, one participant said their philosophy towards eating consisted of ‘quality over quantity’.

Others volunteered phrases like ‘I really regret eating healthy today – said no one ever’ and ‘I train to be strong; I eat to be lean.’

Lead researcher Anna-Leena Vuorinen, of VTT Technical Research Centre in Finland, said: 'These results are encouraging because they imply that instead of putting restrictions on one's diet and avoiding favorite foods, weight gain could be prevented early on by learning to listen to inner cues and putting emphasis on the quality instead of the quantity of food.'

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