The consumption of protein-rich foods ``as soon as possible after exercise'' may speed muscle recovery, concludes study co-author Dr. Donald Layman of the University of Illinois in Urbana. The findings are published in the June issue of the Journal of Nutrition.

The study authors explain that leucine -- one of a family of compounds called 'branched-chain amino acids' -- plays a key role in helping muscle cells make protein during recovery after exercise.

Layman and his colleagues conducted a series of treadmill tests in rats. They found that post-exercise muscle protein metabolism occurred at optimal rates when rats were fed leucine-rich foods (versus no food or carbohydrate-rich food) immediately after exercise.

``Leucine appears to have a specific, and apparently unique, impact on skeletal muscle,'' Layman explained in a statement. He said that, similar to the hormone insulin, leucine stimulates a cascade of chemical signals that 'jump-start' the post-exercise protein metabolism process.

``It appears that leucine stimulates the first step in protein synthesis,'' Layman said. The amino acid also ``provides fuel for the muscle and helps to maintain blood glucose,'' he added.

The findings may have implications for the diets of high-powered athletes. Layman recommends that, for optimum performance, athletes ``consume protein in the range of 1.4 to 2.0 grams per kilogram of body weight.'' Converted into pounds, this would mean that a 175-pound athlete would consume between about 111 grams to 159 grams of protein per day.

Athletes should aim for a diet ``that contains a balance of carbohydrate/fat/protein with protein accounting for 20% to 30% of the calories,'' according to the Illinois researcher. This daily ratio of nutrients should be spread over all meals, including snacks.

Finally, Layman recommends that a protein-rich food -- such as 'energy' bars or drinks, or foods like ``lean luncheon meat'' be consumed as soon as possible after exercise. However, the researchers do not recommend the use of leucine in supplement form, since the exact amount of leucine needed for muscle recovery remains unclear.

SOURCE: Journal of Nutrition 1999;129.