The Great Debate: Fasted vs. Fed Cardio For Increased Fat Metabolism

One of the hot topics today in weight loss is the debate between which type of cardio burns the most stored body fat, fasted cardio or fed cardio. The belief that performing cardio first thing in the morning, while in a fasted state, when liver glycogen levels and insulin levels are low, the body is forced to rely on stored body fat as fuel, thus increasing body fat metabolism. This concept gained popularity in the late 1990’s when Bill Philips published his bestselling book called, Body-for-Life.

“So what’s the Skinny?”

Does the science really back up this theory?.... Well yes and no. Depending which research study you look at you find that both sides tend to conflict with one anther.

So who is right?

Well based on the research I have reviewed I really see no clear evidence that fasted cardio is truly better then fed cardio. For example lets take an individual who is performing 45 minutes of steady state cardio with a heart rate at 60%-70% of its max and they are in a Hypocaloric state, meaning they are taking in less calories then they are burning of each day. This individual will essentially be burning the same amount of calories during that cardio session wither they are in a fasted or fed state.

So what to do?

Eat! Eating a small protein and carbohydrate rich meal prior to cardio training will not only kick start your metabolism for the day, but it will also help boost your energy to get you through the morning cardio session, without having to kill yourself by hitting the track or treadmill feeling famished. Furthermore, pre-workout nutrition will also play a key role in preventing muscle protein metabolism. You work hard for that muscle so why jeopardize loosing it, especially when more muscle mass = more calorie burning?