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Fructose

Posted: Sun Feb 08, 2009 1:44 pm
by toby123
Is it true that dietary fructose is only used to replenish liver glycogen stores and that any excess ends up being converted to and stored as fat?

In which case we should keep fructose and sucrose consumption to a minimum to avoid fat gain? That obviously means cutting out things with added sugar, and cutting down on fruit.

I read this in 'Gaining Mass!' by Anthony Ellis, but searching the net, I am finding it difficult to draw conclusions on this matter.

Posted: Sun Feb 08, 2009 2:10 pm
by TimD
Fructose is used primarily for liver glycogen replacement. That part is true. liver glycogen is used to feed the brain and keep blood sugar levels stable during a fasting period. That's also a good thing. It can also be used as an energy source.

Fructose should NOT be confused w/high fructose corn syrup , In it's most natural form, in fruits such as apples, pears, etc, there is also a fairly high fiber content, which is also a good thing, Now, it doesn't take a lot to top off liver glycogen levels, so, yes, if you OVERINDULGE in fruit, it will probably add to obesity problems, but kept in moderation, should be fine. You just have to use common sense in the matters and not automatically exlude food groups because "it's carb's", or "it's sugar". So, a piece or two of fruit a day certainly isn't going to lead to major fat stores, given the rest of your diet is in order.
Tim

Posted: Sun Feb 08, 2009 4:38 pm
by stuward
The most common source of fructose in the modern western diet is from HFCS. It turns up that over the last 27 years that it's been available people have been consuming ever increasing amounts. They have not been decreasing consumption of other types of sugar so their overall sugar consumption is increasing. Many think that this is a major contributer to the obesity epidemic that is occurring.

There is nothing wrong with having a little fructose in context with the way nature intended, i.e fruit.

Posted: Sun Feb 08, 2009 4:48 pm
by toby123
I have cut down on my fruit consumption by about half. I used to have a lot more, including fruit juice, but then I was doing more cardio. Now I have to be more careful.

You can have too much of a good thing.

Posted: Sun Feb 08, 2009 4:49 pm
by toby123
How do I stop these banners appearing every time I post a message? :mad:

Edit: Hmm, except consecutive messages.

Posted: Sun Feb 08, 2009 4:59 pm
by stuward
Be careful of processed foods. HFCS and added sugar are pervasive. It's always best to eat whole foods and prepare them yourselves.

Posted: Sun Feb 08, 2009 5:56 pm
by ironmaiden708
Fructose vs Glucose it will be less fattening for your body for a few reasons.

1. It passively diffuses into the bloodstream meaning that it requires no energy to absorb, meaning it won't spike your insulin. Glucose is actively transported into the bloodstream making it absorb faster.
2. Fructose is fruit sugars, fruit is a fiber source and as you know it will slow down digestion.
3. Fructose itself is not used as an energy source for the body. To be used it must be converted into either glucose or glycogen which itself will take a period of time slowing digestion.

Posted: Mon Feb 09, 2009 10:19 am
by daniel4738
TimD wrote:Fructose is used primarily for liver glycogen replacement. That part is true. liver glycogen is used to feed the brain and keep blood sugar levels stable during a fasting period. That's also a good thing. It can also be used as an energy source.

Fructose should NOT be confused w/high fructose corn syrup , In it's most natural form, in fruits such as apples, pears, etc, there is also a fairly high fiber content, which is also a good thing, Now, it doesn't take a lot to top off liver glycogen levels, so, yes, if you OVERINDULGE in fruit, it will probably add to obesity problems, but kept in moderation, should be fine. You just have to use common sense in the matters and not automatically exlude food groups because "it's carb's", or "it's sugar". So, a piece or two of fruit a day certainly isn't going to lead to major fat stores, given the rest of your diet is in order.
Tim
Tim, I am a little confused by this. I am following a quite strict Paleo diet which means no carbs from starches, beans etc. The only time I go non paleo is during workouts, which involves a sugar intake during and after.

During a day I eat about 5 peices. I need to so I eat this. But you are saying this much fruit is bad? Is there any chance anyone can explain in more detail? Where should I get my carbs from if it isn't from fruit?

Also, I eat a lot of veggies per day too. I guess on average, I eat about 5-7 kg of fruit and veg per week.

Posted: Mon Feb 09, 2009 11:28 am
by TimD
No Daniel, read it again. I'm saying to use common sense when it comes to eating fruit. It's fine in it's natural form, just don't go overboard. What is that limiting number? I have no idea, it will vary rom person to person due to their metabolism. Obviously, sitting down and eating a truck load over apples is too mych, whereas if you're working hard, maybe 4-5 pieces of fruit throughout the day may be just fine. Don't get hung up on numbers.
Tim