Be In the Mix

BE IN THE MIX 

The rules on post workout nutrition go like this: Immediately after every workout, you need to consume about 40 grams or protein and 60-100 grams of fast-digesting carbs. This combination simulates muscle-protein synthesis and replenishes depleted muscle glycogen stores. Not to mention the ensuing insulin spike that produces its own anabolic effects, helps get more amino acids and creatine into muscle cells and blunts the release of the catabolic hormone cortisol that has negative effects on muscle growth.             

Typically, we recommend that the best carb sources to consume after training are white bread, white potatoes, dextrose, sucrose (table sugar) or other rapidly digesting carbs that spike insulin levels. Yet according to new research, your postworkout nutrition may not be quite that simple: To really speed up carbohydrate digestion and absorption and further boost insulin levels, it appears that eating a mixture of different kinds of cars after exercising is your best bet.            

Researchers from the University of Birmingham (Edgbaston, United Kingdom) performed a series of studies that investigated the effects of combining various carbs  such as fructose, sucrose and glucose vs. glucose alone. Glucose is considered the fastest-digesting carbohydrate – that is, when you’re talking about single-carb sources. Yet the scientists discovered over years of work that when you take in a large dose of carbs such as that recommended after workouts, combining glucose, fructose and sucrose leads to faster digestion and absorption that taking glucose alone.            

The reason for this relates to transporters in the intestines that allow the bloodstream to absorb carbs. Each kind of carbohydrate utilizes a different type of transporter, and if you take in too much of only one type of carbohydrate in a meal, its transporters can get overloaded and its absorption may actually slow down – meaning your muscles don’t get what they need as soon as you’d like them to. Yet eating carbs won’t overload the transporters, resulting in faster digestion and absorption, higher insulin levels and a faster rate of glycogen replenishment. The optimal combination appears to be a 2:1:1 ratio of glucose, fructose and sucrose, respectively. This research out of the UK also indicated that mixing carbs is beneficial only when taking in 70 grams of carbs or more. Since we typically recommend consuming 60-100 grams of carbs after workouts, you’ll likely benefit from mixing carb sources for your post-training meal.  See “Mix-n-Match” below for a list of sample meals containing a combination of beneficial carbs that will both digest and be absorbed rapidly. (Muscle & Fitness, May 2007)