Should You Train Before Or After Eating?

A much-argued topic, knowing if you should eat before or after a workout, can be difficult to know. What to eat, or if you should eat anything at all.

TRAINING FASTED

Scientists have said that exercising on an empty stomach may 'promote more favourable' changes in body fat. The team from the University of Bath studied 10 overweight male volunteers. The participants were asked to walk for 60-minutes at 60 per cent maximum oxygen consumption first on an empty stomach and, secondly, two hours after consuming a high-calorie carbohydrate-rich breakfast.

The scientists took blood samples after fasting and the high carb breakfast and then after exercise. They also took adipose (fat) tissue samples immediately before and one hour after the walking exercise. They discovered that the expression of two genes (PDK4 and HSL) significantly increased when the men fasted – but decreased when the men ate a high-calorie breakfast before they exercised. The increase in these genes suggested that fat was used to fuel the exercise, instead of the food consumed at breakfast.

Dylan Thompson, corresponding author of the study explained that this fat tissue often faces competing challenges. After consuming food, it is busy responding to the meal and "and a bout of exercise at this time will not stimulate the same [beneficial] changes in adipose tissue. This means that exercise in a fasted state might provoke more favourable changes in adipose tissue, and this could be beneficial for health in the long term."

TRAINING FED

If you're opting for more intense workouts - or those longer in duration - then eating can fuel your exercise and stop you getting light-headed. Exercising on an empty stomach has been shown to enhance or increase fat burning but there's a case for and against. Largely it depends on the type of workout you're doing. If you're participating in a higher intensity session, you'll need your fuel stores for your workout - fat isn't the body's favourite type of fuel and the chances are you'll burn more calories than when you're running on empty because you'll be able to maintain intensity.

If you're plumping for a low intensity workout, that might even be a brisk walk, then you can try it on empty. Just ensure you stop if you feel lightheaded or weak."

OUTCOME

It's best not to overcomplicate things and it's important to pay attention to your own needs. Training fasted or fed is a much talked-about subject. Research has shown that training in a fasted state burns more fat during the workout, but training in a fed state leads to higher fat oxidation over a 24-hour period when compared to a fasted state.

The best 'state' is the one that fits with your lifestyle, what your training goal is and the one where you can train at your best. If you're training super early before work, eating and letting that meal digest before training is going to be difficult. Chances are, you'll be better training in a fasted state. If you’re training later in the day you'll probably train better having fully digested a meal beforehand.

The simple answer is for the majority of us, it will make little difference when looking at fat loss over a significant period of time. Just pick the state that suits your training time, gets you the best results and the one that makes you feel the best!