What Should You Eat Prior to a Cardio Session?

Question from David:  Hello! Great post on pre/post workouts. This IS a critical topic. My question is what about cardio only days? I have been told to NOT eat before my cardio only sessions. I follow the pre/post rule for when I am lifting, but only the post rule for cardio days.Your thoughts?

Answer from Martha: Good question. I actually see quite a few people who have been told not to eat anything prior to exercising aerobically(not sure where this info came from). I am assuming that the rational is that you would burn more fat than carbs if you avoided eating carbs prior to exercise.  However the majority of studies have shown that you can significantly increase the intensity and duration of your cardio session if you eat carbs prior to exercising. You don’t see  marathon runners fasting prior to the marathon! Even if you aren’t headed out for a 26 mile run, I would still recommend eating some carbs prior to a cardio session. Carbs are the body’s major source of fuel during exercise. Let’s say you had dinner at 8 pm and then wanted to go for a 6 mile run at 7 am. Your body will have been in a fasted state for 11 hours. The fuel that our bodies use during exercise comes first from blood sugar (and yours would have been on the low side from not eating for 11 hours).  We then use our glycogen stores found in liver and muscles. This doesn’t last too long. We then will start to use more stored fat for energy. The point is that if you don’t have enough glucose in the blood and glycogen stores, you will get tired before you need to.  You will still burn fat when working out even if you eat carbs prior to exercising.

If you want to burn the most amount of fat,  sit on your couch all day long. We burn a lot more fat as compared to carbs while just sitting around. Obviously, I am not seriously recommending you do this … but you get my point.

Bottom line, if you are doing somewhat intense cardio for 40 minutes or more, I would recommend you eat some carbs prior to exercise. The amount of carbs you will need to eat will really depend upon your weight, how long you are going to exercise. and whether or not you are trying to lose weight. I might suggest ~ 150 calories of carbs for a 30 minute workout and 300 calories of carbs for an hour workout. You will need to experiment to see what makes you feel best. Try to pay attention as to whether or not the carbs increase your energy levels. Now if you’ve had a meal that contains some carbs ~ 4 hours prior to your workout, you really don’t need to eat any more (unless you will be doing a really long session).

 Hope that helped! Check out this link for more info on pre-workout meals.