Working Out to Maintain Fitness
Should I be Eating Before Exercise ? Food consumed before exercise is only useful once it has been digested and absorbed. This means you need to time your food intake so that the fuel becomes available during the exercise period.
The time required for digestion depends on the type and quantity of food consumed. Generally, foods higher in fat, protein and fibre tend to take longer to digest than other foods, and may increase the risk of stomach discomfort during exercise. Large quantities of foods take longer to digest than smaller quantities. Generally, food is better tolerated during lower intensity activities, or sports where the body is supported (e.g. cycling) than sports such as running where the gut is jostled about during exercise. A general guide is to have a meal about 3-4 hours before exercise or a lighter snack about 1-2 hours before exercise. You need to experiment to find the timing, amount and make up that best suits your individual needs.
Working Out to Lose Weight
Exercising in a fasted state (8 hours since the last meal) results in a greater proportion of fat being used as the exercise fuel compared to doing the same workload after a carbohydrate-containing meal or snack. However, it is possible that you may be able to exercise harder and for a longer period if you consume carbohydrate before exercise. Overall, this will result in greater energy use and a better contribution to the negative energy balance that is needed to cause fat loss. To make a decision about eating before your workout, it is useful to consider the goals of the session. If your primary goal is to improve performance, have something to eat before exercise. If your primary goal is weight loss, and you will do the same amount of exercise regardless of whether you eat or not, save your meal until after the session.