I have heard conflicting advice about whether to eat before running.

Some have advised that it's better to do the cardio in a fasted state. This usually involves running in the morning without eating anything before the run. It is said to burn more fat this way. See this NYT article on The Benefits of Exercising Before Breakfast.

On the other hand, I have read that it's better to eat something light before the run, otherwise you will tend to lose some muscle. See this NYT article about The Claim: Exercising on an Empty Stomach Burns More Fat.

I'm confused.

  • 1
    Odinzs, for the record, I too have found it impossible to get decisive, scientific, information about this issue. There seems to be many different opinions, and the opinions tend to be just opinions. A further issue is that it must make a huge difference whether you are exercising aerobically or anaerobically, depending on your heart rate - different ideas would apply (surely?)
    – Fattie
    Commented Aug 15, 2011 at 7:47
  • The answer I will give depends on the length and/or intensity of the run. Can you give me some info on a typical run for you? Commented Aug 15, 2011 at 13:42
  • @ryan miller - my typical run is about 5km.
    – Zachary
    Commented Aug 17, 2011 at 23:29

3 Answers 3


Simple answer is no.

For short runs of less than an hour, you certainly do not need to fuel. On longer runs - even ultra marathons - you do not want to eat immediately before running. Instead, on longer runs it is best to fuel on the run either through liquid calories (preferred) or small portions of solid calories. Depending on body size and effort you should consume about ~240 calories per hour during workouts longer than one hour. Your body can sustain itself in this for hours on end.

If you choose to eat before you run, let it be at least 2-3 hours before hand. If you feel like you absolutely need to eat something before a short run, try drinking a glass of water.

On the run fueling options are plentiful. I recommend sticking to products containing natural ingredients (skip high fructose corn syrup products). Some recommended vendors and products are Hammer Nutrition's HEED, PowerBar Perform, Infinit Nutrition, ClifShots, etc.

And I would absolutely recommend fueling with 20 minutes AFTER running. This is the time that your body will be best at absorbing fuel to help you recover and rebuild your glycogen stores. A recovery meal/shake/drink should be somewhere around 200-300 calories depending on body size and duration of exercise with about 20g of protein. The vendor's I mentioned above also have some quite good products for recovery.


I think the answer would depend on your goals you try to achieve with your running.

If you primarily want to burn fat, I think you should not eat before running. This will reduce the amount of available energy of carbohydrates and make your body take more energy from fat reserves. However, make sure you don't feel dizzy or get an upset stomach.

If you are after a good time in a race you should eat a little before running. This will fill up the carbohydrates and make the energy available during the race.

I myself try not to eat or drink too much before running to reduce the "risk" of side stitches, which are said to show up if you have eaten something before the run. (See this question)

Please be aware that I am not a very experienced runner or a doctor. Maybe someone else of this community can back my posting up / or not.


When I look at my fellow runners, I can find just as many opinions as runners. Each of them have their own recipe and stick to it somewhat religiously.

Personally, I usually try not to eat too much on the day before a longer run (18 km or longer) with the possible exception of a banana or like 30-45 minutes before the start and water right up the start.

For shorter runs, I usually just try to avoid eating 1-2 hours before start. Especially anything heavy like meat.

I often go for a short run in the morning (before the rest of the family gets up when it is quite and peaceful) and then I usually just eat a banana and drink a glas of water before I start.

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