Diet, exercise, and energy expenditure (physical activity) define the―energy balance‖ which modulates body habitus. These modifiable lifestyle factors provide an opportunity for therapeutic intervention in the subfertile. The evidence evaluating dietary and physical activity habits are largely observationally based, with multiple groups providing conflicting results. However, the preponderance of evidence appears to support an approach of moderation, with avoidance of high saturated fat diets, low pesticide residue fruits/vegetables, and maintenance of a low to moderate intensity exercise routine. Body habitus, especially in regard to morbidly obese patients, is more difficult to adjust to a meaningful degree. Obesity itself appears to be a risk factor for infertility, although traditional semen parameters do not tend to reflect reproductive impairment. Aggressive lowcalorie diets, and the immediate post-operative period for bariatric surgery, tend to decrease fertility potential. Ultimately, better studies are needed to further our understanding of these lifestyle factors and to inform reproductive urologists to better serve and counsel the subfertile.