4 replies to this topic

[CobaltThoriumG]

For background on the AGE problems with fructose, see section 3 here: http://andersonclan.us/andersonclan_top/ages.html.

So, is there a safe daily fructose intake? How much is too much? How high is acceptable?

Right now, I probably average around 20 grams. I have a plan roughly to halve it, which, halved, would break down as follows:

45g frozen blueberries: 3.86g

2oz Knudsen Very Veggie juice or 31.5g tomato puree (every other day): 2g (average of 1g/day)

4tbs coconut milk: 2g

2tbs almond butter: 2g

2tbs Rejuvenative Zing (fermented beet/carrot product): 0.86g
19.5g walnuts: ~0.65g
total: 10.38g

10.38g fructose = 41.52 calories = ~1.5% of my daily caloric intake

My values for the fructose contents of the above foods may be a little high because I am assuming that all sugar they contain is in the form of fructose. Upon further research (see http://www.nal.usda.gov/fnic/foodcomp/Data/Other/herr48.pdf), it looks like berries contain glucose and fructose in roughly equal parts, coconut has roughly 1.5 times as much glucose as fructose, almonds and walnuts don't have good data (so, let's say half fructose, half glucose), fructose is roughly 1.2 times the glucose in tomato juice and puree, and beets and carrots contain fructose and glucose in roughly equal parts. So, not looking at total sugars then, but only fructose:



45g frozen blueberries: 1.93g

2oz Knudsen Very Veggie juice or 31.5g tomato puree (I ly ly ly like the lycopene. And potassium.) (every other day): 1g (average of 0.5g/day)

4tbs coconut milk: 0.8g

2tbs almond butter: 1g

2tbs Rejuvenative Zing (fermented beet/carrot product): 0.43g
19.5g walnuts: ~0.325g
total: 5.485g

5.485g fructose = 21.94 calories = ~0.8% of my daily caloric intake

That has to be entirely acceptable. Maybe I could even have some more berries. I planned to delete 35g blackberries I had been having with dinner as part of the plan to halve my fructose intake but maybe I don't need to. Might even splurge and go up to 50g blueberries. Woo. Wild man. And, as of today, my only lactose is from whey isolate, which is de minimis.

Edited by CobaltThoriumG, 06 April 2009 - 04:54 PM.

[CobaltThoriumG]

Something I overlooked when I wrote the above post but turns out not to matter much for my diet are the values for sucrose content of foods listed in the USDA link above. So, half the sucrose value should be added to the listed fructose value for total fructose.

[edward]

I don't think there is one universal daily safe intake. It all depends on your metabolic and glycogen status. Your liver can store about 100 grams of carbs as glycogen and your muscles between 250- 400 (depending on how much muscle you have). Fructose can be utilized by the liver and stored there as glycogen but as far as I know can't be readily utilized and stored in muscle tissue, though the liver could convert it to glucose which could then be stored in muscle tissue.

Basically if you liver and muscles stores are low (from low carb or intense exercise) you could eat quite a bit of fructose and it wouldn't be horrible. Still due to some other effects of fructose it wouldn't be that good either. If your glycogen stores are only slightly depleted then you couldn't eat very much fructose. This is all assuming your metabolism is working right which in many people it is not.

To be safe I would only consume fructose from whole food sources like fruit, any processed food with fructose is for me inedible and most processed foods in general I don't eat.

[ajnast4r]

lift hard, eat lots of fruit, end of story.

[nowayout]

45g frozen blueberries: 3.86g

For some reason, for all brands of frozen blueberries that I have tried (Whole Foods, Organic, Wild), the fruit seems to embedded in a syrupy juice (only obvious once you thaw them) that makes it overly sweet compared to fresh blueberries. Since no other ingredients are listed, the syrup is probably also from blueberries, but I suspect that it might be concentrated during processing to make the blueberries taste extra sweet. This is to me a red flag and I avoid it.

To be safe I would only consume fructose from whole food sources like fruit, any processed food with fructose is for me inedible and most processed foods in general I don't eat.

I agree. For example, the glycemic response to juices are known to be different from that to whole fruits. Avoid commercial juices but I wouldn't worry about whole fruit intake (within reason of course).

Edited by andre, 06 April 2009 - 11:28 PM.