Pay attention to carbs
A low-carbohydrate diet is unnecessary for weight loss, and may even impair muscle maintenance and potential growth by limiting exercise performance, Milton says. However, in one study from the University of Illinois at Urbana-Champaign found that when women followed a 1,700-calorie diet for 10 weeks, those who maintained a 1.4:1 carbohydrate-to-protein ratio (171 grams of daily carbs 125 of protein) lost more fat while losing less lean mass (aka muscle) than those who maintained a 3.5:1 carbohydrate-to-protein ratio.
Smith-Ryan explains that you don’t need to go as low as the study did retain muscle mass while losing fat, though. She says an easy 2:1 ratio is ideal. So however much protein you eat (see above), eat double the number of grams of carbs.
Do high-intensity intervals
High-intensity interval training—such as sprints on the treadmill or stationary bike—is effective at burning calories both during exercise and afterward through excess post-exercise oxygen consumption, Milton says. And, unlike steady-state cardio, it recruits type-2 muscle fibers over type-1s, meaning it guards against muscle loss.
With the right work-to-rest ratio, HIIT can even build muscle. Smith-Ryan’s research, published in the Journal of Science and Medicine in Sport found that, over the course of a three-week training program, people who exercised at a 1:1 ratio gained significantly more muscle than those performing 2:1 intervals. For every second you spend sprinting, spend that much resting before your next bout.