Written by Joan Kent28th February 2013
What we eat before a workout is very important, but what we eat afterward is even more important. The main value of eating right after a workout is that we recover well and can train well the next day. Industry guidelines are clear that three days a week of exercise can postpone the inevitable, age-related fitness decline, but more frequent workouts are necessary for fitness improvement. So re-fueling becomes key.
It’s best to eat within 30 minutes after exercise ends. For many people, that will mean eating in the locker room, so convenience is a factor, but we’ll get to that in a moment. First let’s look at three reasons this 30-minute refueling window is critical:
1. Glycogen replacement (repletion) is most effective in that 30-minute period because the enzyme (glycogen synthase) that facilitates it is in its most active form.
2. Missing the 30-minute window can trigger transient insulin resistance that may persist for hours. If that occurs, it can prevent later meals from replacing glycogen as effectively as replacement that starts within 30 minutes.
3. The carb/protein mix stops the cortisol response, which tears down muscle tissue.
Actually, the above three reasons have post-training windows of slightly different durations, but it makes the most sense to eat within the smallest window to cover all bases.
According to Maughan’s Nutrition in Sport and other research, the best post-workout fuel is a combination of starch and protein, in a ratio of approximately 3:1. The original research by Zawadki et al. used a 2:1 ratio, and I‘ve seen 4:1 used in some, but the generally recognized guideline these days is 3:1.
For convenience, I recommend a slice or two (maybe three) of a whole-grain bread that’s easy to store in a locker. Here are a few things to look for in a “refueling” bread:
• Try a bread that’s whole grain but has fairly large air spaces. Large air spaces raise the glycemic index (GI). After training, carbs with a high GI provide faster glycogen repletion. Avoid “dense” breads – they’re healthful, but slower to absorb.
• Look for a carb-to-protein ratio of about 3:1
• You might also try a combination of whole grain and refined flour again for the higher GI. Not as healthful, but still workable as post-training fuel.
• Check the calories. You want bread that’s reasonably low in calories - 50 calories per slice (vs. 80-100 in other breads) is a good target.
The combination of starch and protein is suggested by reputable sources as preferable to sugary recovery drinks, fruit (the wrong post-workout fuel altogether), or the recently touted chocolate milk, which contains mostly sugars. As a final point, it's better to avoid fat in the 30-minute post-training window. Don't use almond, peanut butter, coconut oil or other fat on the bread after training. Those fats are not bad for you (they're good), but fat slows the absorption of carbs. Fast absorption is critical following a workout.