Obesity is not just a problem for women. Lugging excess weight around one’s middle is an especially ugly risk factor for a testosterone-estrogen hormone imbalance. Testosterone plays a vital role in how the body balances glucose and insulin and in fat metabolism in both males and females. Aromatase, an enzyme in fat tissue, converts testosterone into estradiol, a type of estrogen. That can result in a decrease in testosterone levels and a corresponding increase in estrogen levels, undesirable for anyone regardless of gender—although perhaps of particular concern to sexually-active males. Snacks or meals loaded with refined and processed carbohydrates from white flour and sugar can trigger the biggest surge in aromatase. The New England Research Institutes (NERI) reported a study of 1,822 men, which concluded that a man’s waist circumference is the single strongest predictor of low testosterone. It’s a two-way street: obesity can cause low testosterone and low testosterone can contribute to obesity.