Most of us know that we shouldn’t exercise after a big meal. Exercising on a full stomach is generally rather uncomfortable, because blood oxygen gets diverted from digestion to muscles. A light snack some time before a workout is usually the way to go.
However there is new evidence that an empty stomach makes a more efficient workout. There are some downsides, so should you exercise hungry or lightly fed?
The answer seems to be that hungry workouts really can be more efficient. ‘Training fasted’ (as opposed to ‘training fed’) seems to make the body burn more of its fat stores. If you ‘train fed’, carbohydrate is available as glucose in the blood and the body turns to that instead. Some small-scale studies are bearing out this theory.
There is even evidence that ‘training fasted’ can make your body more efficient for future ‘training fed’ sessions. These are the times when your body needs to make use of carbohydrate. Inability to do this efficiently can bring that ‘runners wall’ much closer, or give you a sudden dip in the middle of your weights or cardio session.
Exercising hungry will feel like much harder work. Running on empty also isn’t the best idea if you are doing something that needs concentration. For instance, road cyclists need to be alert. Hungry brains don’t react quickly.
Perhaps the most obvious downside is that exercising hungry can make you rush your workout. Do you have the patience to wait for that post-workout snack?
The only realistic time for ‘training fasted’ is first thing in the morning, but if it works for you then the evidence is in your favour. If you are working towards a race or competition, combine it with ‘training fed’ sessions for the best mix.
As always, it is a matter of compromise and what works best for you. Choose some good muscle building food, experiment with the best time of day for your workout and see what feels best.
Matt's got it right really - do whatever feels best for you. The main thing is that you are exercising, regardless of the time. Feel pleased enough that you are doing it.
I love to exercise first thing in the morning on an empty stomach, then come home and have a big healthy nosh out with carbs/protein/fruit. Nothing makes me feel better! So workout first, grub after is the way to go for me. Don't care what the science says!
not sure it would make too much difference for me, as my body clock simply doesn't do exercise first thing. It is always mid-day with lunch afterwards. Interesting theory though.
I think a morning workout before breakfast works well psychologically too as you feel leaner and therefore more motivated.
Mike - a light snack before a workout is meant to be fine, but doesn't count as fasted, as far as I can tell. But to be honest, it's whatever works for you.
My gym workouts are usually around 5.30pm, 4 hours after eating lunch. I do have a banana before though. Does this still count as an empty stomach?
this is news to me - I do my lunchtime exercise first, then have my lunch as it is more comfortable that way. Not sure if that counts as 'training fasted' but perhaps worth a go.
I love to train first thing in the morning, then have a huge breakfast after. It works for me and fits in with my lifestyle. I don't really care about the science.