Emerging results from randomized controlled trials demonstrate caloric restriction and exercise interventions, resulting in weight loss of 7-10%, are associated with initial improvement in muscle strength and function in older adults; however, in few cases has the effect of caloric restriction, independent of exercise, been evaluated and no randomized controlled trials have examined the role of specific dietary components, as adjuvants to weight loss, on physical function. Evidence supporting a diet-based weight loss approach in obese, older adults with functional impairments has tremendous clinical significance as multiple behavior changes are often difficult to implement and maintain, and many older adults are unable (or unwilling) to engage in the amount of physical activity typically prescribed in lifestyle-based interventions.