Professor Malcolm Law says king-size versions of your favourite choc bars are too full of fat and sugar and are making people fat.
Some of the jumbo size bars are a third bigger than the normal ones but only cost a few pence more.
Shrink portions
The only problem is, you'll be eating many more calories than you usually would.
And with 10% of six-year-olds very overweight, experts want to crack the growing problem of obesity among children as well as adults.
The Independent newspaper says Professor Law wants chocolate and crisp-makers to ban 'over-sized' chocolate bars and shrink other portions by 20%.
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