T Nation

Fruits

In one of the posts Bill Roberts mentioned that fructose shouldn’t be a big part of ones diet as they can’t be used by muscle tissue, that’s news to me…Fruit juices is what I’ve always used for post-workout carbs, is that a mistake?

Yeah, that was news to me too, since I liked to eat fruit after working out. I read somewhere that it’s because fructose isn’t easily converted to glycogen or something like that, and therefore can get easily stored as fat. On the other hand, fruit tastes good, has a low glycemic index, and the source from which I read from was John Parillo who recommends eating 6,000 calories a day to lose weight!

Umm… not all fruit and juice is the same as far as types of sugar… I belive grape is full of dextrose.

The body always replaces muscle glycogen first and liver glycogen second after a workout. But, in the case of fructose (and possibly sucrose), the body replenishes liver glycogen stores first, then muscle cells and fat cells second. So, what I think Bill was trying to say, was that you don’t get a complete/effecient compensation with fructose only (or supercompensation, which is what you want). On another note, including fruit with a high fat meal increases your fat storing capabilities. In regards to grape juice, I believe its high in glucose.

Fruits most certainly have a high GI, stay away from them as a carb source if you are trying to lose body fat.

Fructose is the saccharide that is least likely to cause you to store bodyfat. It has a very low GI. It isn’t as efficient as say, glucose, in replenishing muscle glycogen stores, but it certainly will provide a source of energy for muscle cells. Also remember that fructose is an insulin independent monosaccharide. Meaning insulin or very minute amounts are needed for it to be stored. Most fruits have a low GI. For this reason, they probably shouldn’t be used for post workout, with the possible exception of grape juice, but even that has fructose in it, thus lowering the GI. I think the point Bill was trying to make was that when maximizing the potential to store glycogen, you may want to consume maltodextrin or dextrose. When dieting, however, as long as you’re consuming less than you expend, then fruits certainly won’t make you fat. The article, “The Forbidden Fruit” goes into detail about this. Fruits and fructose have been bashed for too long with little evidence to jusitify it. It has a lot of benefits.

When talking of fruits and fructose, it is important to clarify one point. Fructose is a component of fruit but there are certainly other sugars as well in fruit. Get a nutrition text and find out which fruits have what levels of each sugar. Fructose has a very low glycemic index so a fruit high in this sugar would also have a low GI. Most fruits have different GIs because they have different proportions of dextrose, glucose, fructose, etc. You get the point. Now, fructose itself isnt evil when consumed in moderation in the diet. If fructose makes up the main portion of your diet, however, you could have problems due to increased LDL, decreased HDL, etc. The reason for this is that fructose has a very unconventional way of being metabolically processed. Because of its structure, it cant be metabolized like glucose. Instead it has to go through extensive processing in the liver. This is why Bill recommended another sugar for postworkout glycogen resynthesis. You see, fructose is slow to get into the blood (low GI) AND when it finally gets there, it doesnt even go directly to muscle but instead goes to the liver. So, postworkout nutrition should not include alot of fructose. Personally I eat some very high GI carbs with a small amount of fruit for the post workout. Probably 80grams to 10grams of nonfructose-fructose. Not for any other reason than I really like eating frozen blueberries and strawberries in my cereal and cottage cheese. For the remainder of the day, though, moderate fructose consumption is fine. Fruits taste good and are very good for you!

What foods contain a lot of glucose that I can consume after workouts??