If you've ever tried to exercise after having not eaten in a while, you know the results can be disastrous. That's because your body has no ready source of fuel to power working muscles. Yet you don't have to slam a sandwich: Caffeine can also help give your body energy for a workout. "Studies show that caffeine can increase levels of blood fats," allowing your body to use fat instead of carbs for fuel during exercise, says Burke. This lets your body save glycogen stores – your muscles' primary fuel source – for later in your workout when you need them.
Credit: Milan Zeremski / Getty Images
Powered By ZergNet
Sign up to receive the Men’s Journal newsletter and special offers from MJ and its marketing partners.
Gear of the Year
103 Must-Have Gadgets, Tools & Toys
Plus: The Plan to Save Africa's Rhinos
ON NEWSSTANDS NOW