An apple a day could keep flab at bay - as long as you eat the peel.
The chemical behind the apple skin's waxy sheen is credited with helping the body burn extra calories.
Mice fed fatty food laced with ursolic acid ate more put on less weight than those who given the fatty food without the medication.
Fat fighter: A chemical behind the apple skin's waxy sheen is credited with helping the body burn extra calories
The compound also seemed to keep blood sugar levels in check and stop the liver from becoming clogged up with fat, the journal PLoS ONE reports.
The University of Iowa research revealed ursolic acid, which is also found in cranberries and prunes and in basil, oregano and thyme, to boost the growth of muscle and brown fat, a calorie-hungry version of fat common in babies.
Dr Christopher Adams said: 'Since muscle is very good at burning calories, the increased muscle in the ursolic acid-treated mice might be sufficient to explain how ursolic acid reduces obesity.
'However, we were surprised to find that ursolic acid also increased brown fat, a fantastic calorie burner.
'This increase in brown fat may also help protect against obesity.'
Ursolic acid's muscle-building properties could also be of benefit, stopping pensioners' muscles from wasting as they age and cutting their risk of hard-to-heal fractures.
Dr Adams now wants to work out if apple peel is as good for people as it is for mice.
This would allow him to work out how many apples we'd need to eat to make muscles bulge and waistlines shrink.
If the number is very high, ursolic acid could be concentrated in a pill or supplement.
Read more: http://www.dailymail.co.uk/news/article-2162425/How-apple-skins-waxy-sheen-help-slimmers-peel-weight.html#ixzz1yR2tlSzl