Protein is a necessary component in the body for energy. It also plays a key role in creating and sustaining muscle mass. Of course, muscle mass and general muscular strength is imperative for the body to remain mobile, but it also helps prevent injury.
The elderly are at a particularly high risk for severe injury that may come with movement or falling because they have less muscle mass than younger people. This is not only due to a less active lifestyle, but nutrition as well. Many older people do not realize their diets are actually protein deficient. Others slowly cut out things like meat because it is more difficult to prepare and tougher to chew.
Studies have shown, however, that if people over the age of 55 maintain a diet that is high in protein, they are more likely to increase (or maintain) energy and less likely to lose muscle mass as they age. Nutritionally, consuming an adequate amount of protein also combats over-eating (and filling up on empty calories or excess carbohydrates) which of course contributes to becoming over weight and even obese.