Why meat-free diets put the brakes on muscle growth...

A diet containing more meat can help older men build muscle faster.

A group of men, aged between 51 and 69, were split into two groups. Both groups followed the same weight training program, which involved two workouts each week. Each session included exercises for both the upper and lower body.

Group one consumed their normal diet, which included meat, poultry and fish. Group two eliminated all meat from their diet. After 12 weeks on the program, men consuming a mixed diet gained more muscle and strength than those consuming a meat-free diet.

The older you get, the more muscle you lose. This age-associated loss of muscle (known as sarcopenia) means that older people can quickly lose their independence. Simple tasks such as getting out of bed, shopping for food - even getting out of a chair - become a real challenge.

However, this study showed that just two days a week of weight-training, combined with a diet containing meat, can help boost muscle growth, even in men up to 69 years old.

So why was it that the meat-free group actually lost muscle? Unfortunately, the research team offer no clear answers. However, they did make the following suggestions.

• Previous studies show that individuals consuming meat-free diets have lower testosterone levels, which could lead to slower muscle growth.

• Protein intake in the group consuming the normal diet was 16% higher than the meat-free group, which may have contributed to gains in muscle size and strength.

Whatever the reason, if you're training to build muscle, make sure to include some meat in your diet.

Reference
Campbell, W.W., Barton, M.L., Cyr-Campbell, D., Davey, S.L., Beard, J.L., Parise, G., & Evans, W.J. (1999). Effects of an omnivorous diet compared with a lactoovovegetarian diet on resistance-training-induced changes in body composition and skeletal muscle in older men. American Journal of Clinical Nutrition, 70, 1032-1039