My client Teresa is working on perfecting her post-workout meals to maximize lean muscle gain while losing fat. She asked me today:
I was wondering if a banana is a good post workout food and why it is/isn’t? I have heard both… Thanks for your help. -Teresa
The goal of post workout carbohydrate intake is to raise blood glucose, which in turn triggers insulin release, and the combo of circulating insulin and glucose refills glycogen stores in the liver and muscle cells, and stimulates protein anabolism for muscle growth. (Bonus: It also quells sweet cravings later in the day.) The most effective types of carbohydrate for these effects are starches or glucose.
Fructose is metabolized to glucose in the liver, but most of it ends up going toward liver glycogen synthesis, with little released as free glucose into the bloodstream. In that way, much of the carbohydrates from fructose don’t end up being available for refueling or building those muscle cells. Not to say this is the end of the world, but we’ll call it not-optimal.
So back to you and the bananas. Like most types of fruit, bananas are composed of approximately equal amounts of fructose and glucose. There’s about 10 grams of each in an average size banana. Not too bad, but I wouldn’t use ONLY bananas or other fruit for your post-training refueling. If I feel like a piece of fruit with my post-workout meal (for my taste buds), I’ll have it, but I stick with starches for the main carbohydrate source at that meal (for the functional advantages).
Since your plan is to include 40 grams of carbohydrates post-workout, I’d stick to 1/2 a banana (10 grams carbohydrate) and get the other 30 grams from starchy sources like oats, sweet potato, quinoa, yam, or rice.