Through shared pathophysiologic mechanisms, obesity exacerbates the age-related decline in physical function, which leads to frailty and disability. Obesity and aging are characterized by chronic low-grade inflammation, which contributes to reduced muscle quality and protein control mechanisms as well as to diminished muscle anabolic response. Obesity causes oxidative stress and inflammation, which increases telomere shortening. Calorie excess increases ROS formation, which damages nucleus, endoplasmic reticulum, and mitochondria and promotes cellular senescence. Given the persistence of DNA damage associated with altered DNA repair proteins in obesity and aging, it is thought that inability to repair DNA may be the principal molecular event that underlies accelerated aging. Calorie restriction in combination with exercise slows biological aging by protecting against the molecular and cellular damages that occur in obesity and aging. Promising approaches such as Time Restricted Eating, Mediterranean Diet, and Senolytics need further investigation.