I always knew that athletes and bodybuilders took nutrition to a different level. In my political blog I've occasionally mentioned an odd fellow Oracle Apps DBA I met on a gig in the late 1990's at a specialty box manufacturer (e.g., boxes used for CD or DVD collections) in the west Chicago suburbs. I was actually in decent physical shape but I seemed to have a resistance level at about 220 lbs. I knew he was a fairly serious gym rat, but I don't know if he was an amateur bodybuilder. He gave me a couple of EAS powder packets and even offered me $50 to throw out everything in my refrigerator. He didn't go too much into his diet, except he mentioned dipping bread into virgin olive oil. (I didn't take him up on his offer.)
I remember in my battles against the Atkins diet fundamentalists back around 2003-2004, I never really liked what I considered over-simplistic daily carb gram caps which were the same held regardless of activity levels. I knew that diets often resulted in an undesirable loss of muscle, a lot of an initial 6 pound or so weight loss was mostly water and I believe related to a drop in glycogen stores. One can conceptualize glycogen (in liver and muscles) as stores of working quick-energy supply. Starches, like the white foods (potatoes, rice, bread), contain glucose, which in conjunction with insulin feeds muscle glycogen, while the fructose in fruit is metabolized by the fiber. Why is glycogen important? Among other things, lack of an energy store affects our energy levels to exercise and can also result in the loss of muscle (which may be used to replenish glycogen). Insulin is also a fat storage mechanism.
At the current time I'm still doing my background research on the topic, and I'm sure that bodybuilders would find my discussion inadequate. The nature and extent of carb consumption should vary on activity level, but some carbs, say complex carbs like whole grains, may be consumed at an interval long enough to ensure that the carbs are metabolized, available for use during a subsequent workout. Then a second feeding occurs after the workout when the glycogen levels are depleted. So we can think of glycogen levels as sort of a thermostat; we never want to overflow glycogen, with excess carbs metabolized as fat, and we never want our glycogen to deplete to the point we lose muscle. [One source suggest excess carbs are converted into palmitic acid which suppresses our sensitivity to the hunger hormone leptin, i.e., we may overeat because we feel satiated later.]
Glycogen levels are naturally lower in the morning when we wake up, and insulin sensitivity is higher in the morning and after workouts. Insulin sensitivity is critical to efficient delivery of glucose to cells. Growth hormones, which naturally decline with age, are also useful in muscle growth and sugar and fat metabolism. Growth hormone generation can be stimulated through anaerobic (strength-training) exercise and can be inhibited by high levels of insulin. Insulin production is stimulated by the consumption of faster-digested, higher-glycemic foods (like the white foods and fruit juices). The above source suggests post-workout some glycogen can be replenished without insulin.
[I think this discussion is somewhat nuanced in the case of people with insulin resistance (metabolic syndrome, predisposition to or diagnosed with type 2 diabetes, etc ) Insulin resistance can be highest in the morning. This has obvious implications for the timing and types of any carb consumption and exercise.]
Here are some practical suggestions:
- Work some strength training into your exercise routine. One heuristic is to consume up to a quarter of your daily carbs in your post-workout. The timing of your exercise routine can also be important; for example, if your insulin sensitivity (vs. resistance) is higher in the morning, you may want to do strength training then.
- Don't eat carbs solo, particularly at the end of the day. In your meal/snack with carbs, include protein.
- Generally choose "good", complex, slower-digesting carbs to smooth out insulin levels. There is one general exception for fitness experts: post-anaerobic workouts, faster-acting carbs, like a plain baked potato, will replenish muscle glycogen faster (when speed is of the essence).
