"Caffeine causes the body to rely more on fat for fuel during a workout, rather than glucose," Aceto says. "But the caffeine effect is lessened when you eat a high-carbohydrate meal with it." Drink 1-2 cups of black coffee within two hours of working out, and emphasize healthy fats and protein if you're drinking it with a meal or snack. Skip the cream and sugar (which add unwanted calories and fat), and avoid drinking coffee at other times of the day; doing so can desensitize you to the fat-burning effects of caffeine.
As a nutrient which raises the metabolic rate probably faster than any other, lean protein is favored by bodybuilders for its fat burning properties. As well as encouraging muscle growth through its conversion into the amino acids needed to rebuild damaged tissues larger and stronger, protein, due to the complexity of its composition, requires additional energy to be properly digested. If we do not eat enough protein the body will break down muscle tissue to ensure there is enough of it to fuel the many biological processes that require it. So, to boost the metabolism to encourage fat burning it is essential that we at all times consume enough protein.
Make sure to follow up leg day with a muscle-replenishing protein shake. According to a study published in the journal Sports Medicine, supplementing resistance training with whey protein helps your body build lean muscle. And the more metabolism-boosting muscle mass you pack on, the more fat you’ll burn, even at rest. What’s more, the study showed that the whey and resistance workout combo also improved upper and lower body strength. Want to kick up the fat-loss a notch? Researchers noticed that these glorious benefits were enhanced when whey is combined with creatine.