The Debate
There is much debate about eating and exercise – whether you should eat before, during and/or after training.
Sorry to bust your bubble, but most of this debate is for money. Companies want you to buy lots of their product, so they tell you it’s great to eat before during and after a workout for various reasons. Most of it is ridiculous unless you are training for an Iron Man or a marathon. Nope, not even you half-marathoners really need food during a race.
During exercise, your body relies on fat stores, muscle glycogen, and liver glycogen for energy. Glycogen is the body’s storage form of sugar.
Short, intense exercise – think sprints or heavy weightlifting for short sets – is anaerobic, meaning it does not require oxygen to provide energy. Here, glucose (blood sugar) provides “instant energy”. This is great, but does not last very long. That is why you cannot sprint at top speed over 400 m (possibly 800 for well-trained athletes).
Long, slow duration exercise – think running 1-5 miles, training for 30 min – 1 hour, or step aerobics – is pretty much anything lasting over 15-20 min. and is aerobic, meaning it requires oxygen to provide energy. Here, fat provides the main source of energy which allows distance runners to keep going and going and going. Liver glycogen is also depleted in about 2 hours.
After long duration exercise, your liver may be depleted of glycogen and needs a refill. There is benefit to eating within 30 minutes of high intensity or endurance exercise.
Certain foods are perfect for this, namely yam/sweet potato, bananas (all glucose), and melons are all excellent choices.
Eating within 30 minutes of training “tops off” your liver glycogen and promotes quicker recovery.
The truth is that unless you have extreme goals, you don’t need extreme eating practices. Lots of shakes and bars were developed with professional bodybuilders and triathletes in mind. Unless you are one of those, lay off the eating constantly because you can’t “outwork” a bad diet.
(photo credit (c): http://muscularmom.wordpress.com)