Protein-based sports drinks are of no benefit to the performance of athletes, scientists have concluded.

The sports-drink industry makes millions of pounds from selling drinks and other supplements to people who want to increase their energy and stamina while exercising.

But when scientists at the University of Bath reviewed the effects of the supplements, they found the drinks offered no more benefits than the protein found in a normal balanced diet.

Dr James Betts, from the university's Department for Health, reviewed the results of all existing research into the effects of supplements containing carbohydrates and protein. Dr Betts' findings will be published in Medicine & Science in Sport & Exercise.