OK, so eating before a cardio-focused workout designed to cut bodyfat or get you a ripped torso might seem counter-intuitive. You’re aiming to burn bodyfat as fuel, right? While this is true, starving yourself before a hard workout is likely to make you put on bodyfat, rather than lose it.
The thing is, unless you’re going for a super-low intensity, super-long endurance session of 2-3 hours you’ll probably be doing an intervals-based circuit, such as Bodypump or Insanity, at high intensity. ‘During low-intensity aerobic exercise fat oxidisation occurs while exercising and stops afterwards. During high-intensity exercise your body oxidises carbs for energy, not fat, but then afterwards and for a long period, oxidises fat to return your systems to normal,’ says Mark Lauren ex-special forces fitness trainer and author of You Are Your Own Gym. In fact your body burns fat at an accelerated rate for up to 72 hours after hard exercise.
When your body burns carbs for energy it takes glycogen stored in your muscles and liver. ‘You can only store 400-800 grams, or 1,600-3,200 calories at a time,’ says Lou Schuler strength and conditioning expert and author of The New Rules Of Lifting. ‘When you are resting a healthy body will burn more than 50% fat, but during exercise the ratio gradually shifts - the harder you work the more you will burn carbohydrates for fuel.’ he says.
All this means if you go into a workout energy depleted you will not be able to work so hard and you may end up burning precious muscle mass for fuel. Worse than that, you will actually end up burning less bodyfat overall because the intensity was not high enough.
Try eating an energy bar or something similar with a mix of slow-release carbs and fruit 1-2 hours before your workout - or if you get caught out then an isotonic energy drink 30-20 minutes beforehand. That way you’ll be pre-fuelled and ready to blast your body into the fitness-boosting, fat-melting zone…
Advice is for information only and should not replace medical care or recommendations. Please check with your GP before embarking on exercise or nutrition regimes for the first time.