fruit and timing
- 07-18-2010, 12:15 AM
- 07-18-2010, 12:25 AM
My belief is fruit is fine any time except the last 4-6 hours of the day. 60-70% of the carbs in my diet come from fruit.
- 07-18-2010, 12:33 AM
i hate how much it costs, i work at a grocery store and the raspberries are 250 for 60z which only provieds like 20g carbs, WTF 2.50 for 20g, thats more expensive than protein!!! wow
07-18-2010, 03:03 AM
Fructose has a bad effect after about 1 serving of fruit a day. Post workout a carb and protein combo is best.
07-18-2010, 04:01 AM
07-18-2010, 06:35 AM
07-18-2010, 12:44 PM
well the problem is that i have seen studies in rats, yes i know its nt humans, that showed the body created a resistence to leptin, and also that fructose is the only sugar that needs to be converted to fat first then to glucose, so it is the most likely to be stored as fat...
07-18-2010, 02:07 PM
Secondly, fructose is not converted to fat first but it does have to be metabolized to glucose in the liver. This is a double edged sword. The benefit is that it takes longer to process (lower GI), the downside is that it can preferentially go into liver glycogen stores rather than muscle.
Finally, anything with positive calories will make you fat if you eat enough of it.
07-18-2010, 02:22 PM
So, not sure what you are reading. There WAS a study done by Shapiro, et al. (2008) that indicated "that chronic fructose consumption induces leptin resistance prior to body weight, adiposity, serum leptin, insulin, or glucose increases, and this fructose-induced leptin resistance accelerates high-fat induced obesity." (Shapiro, et al., 2008, p. R1374), but this in in CONJUNCTION with a HIGH-FAT diet and other factors are involved, and it was specific to testing "the hypothesis that chronic fructose feeding induces leptin resistance, which in turn could predispose animals to increased weight gain in response to a high-fat diet." (Shapiro, et al., 2008, p. R1374). ANIMALS. IN CONJUNCTION WITH HIGH-FAT DIETS. You need to really READ research articles.
On the subject of leptin resistance, yes, this can occur, but like almost everything, it IS reversible.
07-18-2010, 02:32 PM
sorry rosie but it was over a year ago that i read the study, and yes as i recall it was a high fat diet, but when they through out terms like that its hard to narrow down what a HIGH fat diet is, i mean i take about 80g per day at 198lbs, would the DR consider that High moderate or low? and thats on about 2800 calorie diet so that would be 720/2800= ~26%fat in my diet.....
and you and Nitrox have conflicting data, that fructose is converted to fat first, hes saying it is converted first but is preferentially converted to glucose in the liver, but there are many circumstances that need to be defined before you can say that the fructose that was converted to fat will then be stored as glycogen, I.E. timing, calorie expediture after ingestion and prior to ingestion.....
07-18-2010, 02:44 PM
Hepatic fructolysis results primarily in liver glycogen replenishment. Once hepatic glycogen stores have been replenished then fructose metabolism is primarily directed towards triglyceride synthesis.
07-18-2010, 02:51 PM
07-18-2010, 03:07 PM
Once fructose is absorbed, it goes to the liver and converted to glucose, not fat. If you are hypercaloric then the resulting glucose MAY be stored as fat depending on the circumstances.
07-18-2010, 03:12 PM
If hypocaloric then insulin levels will be lower and glucagon will be increased which triggers glucose release. As in, as fructose is converted to glucose it will go to fueling immediate energy needs.
On the other hand, if hypercaloric then glucagon will be lower and insulin will be elevated which down regulates stored glucose release.
07-18-2010, 03:18 PM
Best I can find at the moment... I'm trying to do you better justice than simply linking to wikipedia, although IMO their science articles are more or less on point.Source??
 Enhancement of glycogen concentrations in primary cultures of rat hepatocytes exposed to glucose and fructose. M A Parniak and N Kalant
 THE EFFECT OF FRUCTOSE ON HEPATIC SYNTHESIS OF FATTY ACIDS
Not necessarily. Glucose has a different metabolic pathway. I want to say that galactose is similiar to fructose... although I don't have the time or the citations to back that up that statement at the moment.adn wouldnt this be true of all carbohydrate sources??
07-18-2010, 03:24 PM
07-18-2010, 03:32 PM
07-18-2010, 08:25 PM
No, the data was not conflicting. As said, fructose does not convert to fat - it is converted to glucose (simply put). And note that glycogen and glucose are not the same thing; glycogen is made up of glucose molecule (i.e. it breaks down to glucose).
I recommend that you actually get a physiology and nutrition textbook, to see how each macronutrient is digested and absorbed and then oxidized in the body (i.e. the metabolic pathways that it goes through, etc.).
07-19-2010, 10:05 AM
i actually have a Bachelors in nutrition but we never covered this topic specifically, we covered carb digestion in general never fructose specifically....
and when i approached the teacher about it she blew me off because the study was not fruit friendly, (nice to have open minded professors huh...)
either way i was reaching for an answer, and thank you very much for the info rosie, it makes sense and i forgot that all to important detail that the rats were fed high fat and high fructose corn syrup..... makes a LARGE difference.....
great info guys thank you very much....
NOW WHO HAS THE GI FOR BROWN RICE SYRUP??
07-19-2010, 02:55 PM
No worries. And yes, fructose from fruit and fructose from high fructose corn syrup are two VERY different animals - no way can you make any comparisons!
Re brown rice syrup GI, it's ~25 (this should be in a table in the back of one of your nutrition textbooks).
07-19-2010, 04:29 PM
07-19-2010, 04:51 PM
07-19-2010, 08:03 PM
07-19-2010, 08:29 PM
07-20-2010, 01:39 AM
Burke, L. & Deakin, V. (Eds.). Clinical sports nutrition (3rd ed.). (p. 175-199). NSW, Australia: McGraw Hill.
Marieb, E. N. (2004). Human anatomy and physiology (6th ed.). San Francisco: Pearson Benjamin Cummings.
McArdle, W. D., Katch, F. I. & Katch, V. L. (1991). Exercise physiology: Energy, nutrition and human performance (3rd ed.). United States of America: Lea & Febiger.
Wardlaw, G. M. & Hampl, J. S. (2007). Perspectives in nutrition (7th ed.). Mc-Graw Hill: New York, New York, USA.
Any decent textbook will cover this.
07-20-2010, 07:55 AM
07-20-2010, 10:28 AM
07-20-2010, 11:25 AM
So the ideal post-workout carb would be something with lots of fructose since it goes directly to the liver to be converted to glucose?
On that note wouldn't ANY type of monosaccharide be a good post-workout carb?
I take 20 oz of gatorade with my creatine and beta alanine after I workout. It has sucrose and dextrose, a DISACCHARIDE and MONOSACCHARIDE. I know the DI takes longer to digest so would I be better off making my own blend of say... water and table sugar instead?
07-20-2010, 03:10 PM
The time difference between when carbs from gatorade and something like fruit juice start being absorbed into your blood stream is a matter of minutes. However gatorade has refined carbs and empty calories. Is the sake of a few minutes worth consuming junk food? Your call.
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