As people age they lose muscle mass, about 1 percent a year starting in middle age. That loss, called sarcopenia, is a major reason for continuing strength training throughout life.

Recently, British researchers may have found a clue to why muscle loss may occur, and it could have to do with eating.

Researchers from the University of Nottingham School of Graduate Entry Medicine and Health in Derby, England, studied two groups: eight younger people, average age 25, and eight older people, average age 65. They were tested before breakfast; then they were given a small amount of insulin to replicate their body's reaction after eating breakfast.

By following an amino acid that showed how much protein was being broken down in leg muscles, the researchers found that in the younger subjects, muscles were able to use insulin to halt muscle breakdown, while muscles in the older participants could not.

They also discovered that the younger people had greater blood flow in their legs than the older people, causing speculation that the older people might be getting lower amounts of nutrients and hormones. Weight training, they believe, could help maintain those crucial muscles.

The study appears online in the American Journal of Clinical Nutrition.