This is an approach to exercise that really makes sense. For some of you it may be completely contradictory to what you believe. A quick snack before exercise will give you an energy boost, right? Wrong, whatever we eat will be packed away in a cell as glucose or fat but only if we can digest it. Eating before exercise may not be the best time to eat as your body will be preparing you for fight-or-flight. This means that all energy will be directed towards your muscles and away from your digestive system and you won’t be able to digest a thing! Your pre-exercise banana will be sitting there in your stomach like a lead weight, causing additional problems.
The problem is that every meal we eat creates an unwanted inflammatory reaction. It does not make a difference whether it is a quick snack or a sit down dinner. Don’t get me wrong, inflammation is sometimes necessary when we cut or injure ourselves or have surgery. It is the normal response to wound healing. But when it affects the whole body it can cause damage. What is puzzling is that genetically we are identical to our Stone Age ancestors. They did not have fridges and food packaging that kept their food fresh and clean. Yet we know they did not have this negative whole body reaction every time they ate. What we do know is that they would have had to move around and forage to find food. It is this movement that can produce an anti-inflammatory substance capable of killing bugs (2).
Eating before exercise can affect our performance. According to the Swedish School of Sport and Healthy Sciences, laying off the energy snacks can help us use calories in a more efficient way even in highly trained athletes (3). Carbohydrates can cause a drop in blood sugar levels and reliance on them may affect our ability to burn fat efficiently. This is what can happen during an endurance event when we ‘hit the wall’ after stores of glucose, or stored carbohydrate, have run out. We cannot make the switch from glucose burning to fat burning (4). By training on empty stomach we are giving our muscle cells no other option but to burn fat.