13 Best Weight Loss Diets for MenBelow, nutrition experts list the 13 best diets for guys looking to lose weight (and not lose any muscle mass in the process). It’s also been helpful in boosting brain health, building stronger hearts, and (you guessed it) weight loss. “High-fiber diets are also incredibly effective at leading to long-lasting weight loss,” says Moskovitz. The fiber+protein combo can tip the scale toward weight loss, especially for those with health situations where dropping pounds is unusually challenging. “Although the concept of mindful eating is not a weight loss diet, mindless eating is the most common cause of overeating and weight gain,” warns Moskovitz.