In the U.S., most older women are overweight or obese, which can harm functional health like rising from a chair. Weight loss diets that are higher in protein are popular as they often cause greater body fat loss while keeping muscle. Adding exercise with weight training to a higher protein, weight loss diet may result in greater body fat loss. Plus, this combination might also be best to keep muscle mass and strength and improve physical function. This study randomly assigned older women into three weight loss groups for six months: 1) higher protein diet with exercise, 2) higher protein diet without exercise, and 3) typical protein (control) diet with exercise. All groups lost a similar amount of weight and body fat. The exercise groups had similar muscle strength and physical function improvements, even with different protein diets. Compared to the exercise groups, the higher protein diet with no exercise group lost strength and reduced physical function benefits. Exercise seems to be more important than increasing dietary protein to maintain muscle strength and improve physical function in older women.