Fructose isn't just found in fruit. It's a type of sugar, often prescribed to diabetics as a replacement for other sugars. Fructose is peculiar in the fact that it CANNOT be taken directly to the muscles. First it is converted to glucose in the liver and stored there. Once the liver's storage capacities are exceeded or the body needs more glucose, THEN it's released to the bloodstream in the form of glucose. This glucose needs insulin to be stored in the muscle. My point? From the point you want an apple to the point where that sugar is actually available to your muscles will be a considerably long run. For this reason, especially for those who didnt know, fructose should never be consumed either prior or post workout. It'll degrade both. An apple contains 20 grams of fructose, and those will be 20 grams of sugars you best not count on.
I don’t really care what anyone says… fresh fruit is good for you! (when not excessive and late in the evening, of course). Interresting facts, though. This isn’t a flame by the way, I just like to respond more often now that it’s so much easier.
While best not consumed for carbs after training, fructose does have its uses. See T-mag article: http://t-mag.com/html/body_95forbid.html
Let me point out that when you get fructose from an apple, you're also getting enzymes that aid in the processing of fructose. That means it's a better scenario. The problem comes when you get your fructose from a can of soda which contains an average of 40 grams of it. And for fuck's sake, this only applies just before and after your workout. Eat all the apples you want at any time during the day. Im referring to this particular window around your workout. John Berardi has said it over and over. So have other t-mag contributors.
Just want to make a slight correction. Yep, fructose is metabolized only in/by the liver. It can either be stored as liver glycogen or converted to triglyceride. It will not be directly converted to glucose in the liver to be utilized as blood glucose. However, liver glycogen can be mobilized to maintain blood glucose levels. This would be a rather indirect scenario, but if this is what was referred to, then it is correct.
Interestingly, while fructose itself doesn’t exert much of an impact on blood glucose levels, it seems to exert an insulinotropic effect. Quite interesting.
Good point about the soda, Steel. However, I don’t think many of us are drinking regular sodas. Anything with high-fructose corn syrup is going to wreak havoc, though. You get a real nice tandem of cranked up insulin and production of triglycerides.
So, post workout, what are you looking for? I thought an insulimic response–in order to shuttle protein to the muscle. Are you also looking for glucose to restock the muscle stores?
Wait, I think I just answered my own question.
Fructose as found in FRUIT only, is great to digest first thing in the morning if you don’t plan to work out shortly after. The reason being, our liver glycogen stores are depleted during sleep. You wake up with depleted liver glycogen so those must be replenished and fructose is sent to the liver first, therefore making it the obvious choice at this time. I would recommend eating plenty of fruit on an empty stomach as any starches, fats or even protein will not allow the fruit to be digested properly. You can then eat other foods about 30 minutes or more after eating the fruit. This would be ideal.