Originally Posted by lattin1
Chocolate Milk?!!? Maybe I'm missing something here but that sounds like a horrible thing to drink post workout. First off, the protein in milk (casein) digests very slowly so when you get done with a ride and your body is screaming for protein to repair damaged muscle tissue the last thing you want to do is eat/drink a protein that takes longer to digest. Whey protein is far superior post-workout because it is processed by the body much quicker. Second, chocolate milk obviously contains sugar which is a high GI (Glycemic Index) carbohydrate. It digests fast and the energy it contains is used fast. When you consume high GI carbs after a workout it causes your insulin levels to spike and then rapidly drop which is not good for muscle recovery. After working out you should consume low GI carbs like oatmeal, brown rice, whole grains. Low GI carbs create a sustained increase of insulin in the blood stream which allows for quicker recovery.
Actually, you have to take timing into account here. You
DO want as high-GI a carb as possible to charge up the depleted glycogen stores after a workout. The insulin spike is
EXACTLY what you want as well. Insulin triggers glut-4 in the cell membrane and transports glucose from the bloodstream
into the muscle cells; right where you want it. That's why a 4:1 carb-protein mix is ideal because it generates a higher insulin-spike than carbs alone.
Also the most pressing thing to get is glucose into the muscle-cells, not protein. You've got a 20-30 minute window when glucose-transport occurs much faster than normal. Best to get glucose in at this time. If you do not have sufficient glucose in your blood, the actual muscle tissue is catabolized and converted to glucose to restock the glycogen stores. This muscle-tissue is preferred because it's nearby. Ingested protein
DOES NOT ward off muscle-catabolism due to low blood-glucose. So it's more important to get carbs in than protein after a ride.
The muscle rebuilding actually occurs hours later. And the protein that's used for that comes from an inter-cellular amino-acid pool. This supply is an immediate source. The ingested protein, aside from taking a long time to digest, just goes towards replenishing this amino-acid pool later.
It digests fast and the energy it contains is used fast
Digestion-rate and metabolism is completely independent. Your body only burns calories at a rate that's required to meet the current level of activity. How fast you digest something has nothing to do with your energy requirements. If you're riding at a 500-cal/hr pace, you're not going to be riding faster if you eat high-GI vs. low-GI carbs. The high-GI faster-digesting carbs will just help you suck in more calories per hour so you can ride
farther before bonking, but it won't do anything to make you go faster.