The overarching goal of this project is to conduct a comprehensive characterization of weight loss induced by using a PB diet with regular exercise in people with MAO, followed by a comparison of the effects of this study with those from another study that is evaluating the effect of the same amount of weight loss induced by using a PB diet alone, without exercise. Specifically, we will evaluate changes in body composition, body fat distribution, cardiopulmonary function, muscle strength, the plasma metabolome, insulin sensitivity, beta-cell function, systemic and adipose tissue inflammation and immune system function, adipose tissue and muscle cellular metabolic pathways, and the gut microbiome to determine cellular, multiorgan, and whole-body effects of PB diet alone and PB diet plus exercise. Accordingly, this study will fill two important gaps in our knowledge that have considerable physiological and clinical significance; the data from this study will provide: 1) a better understanding of the effects of a PB diet plus exercise on a series of key outcome measures, and 2) the potential additional benefit of adding regular exercise to a PB diet.