Conclusion
For athletes in the midst of a race, or in need of rapid recovery for a second race on the same day, speedy glycogen replenishment may be the endpoint to optimize. If so, they should eat a sugar drink composed of roughly 70% glucose and 30% fructose and galactose.
This is closer to PHD diet ratios than to Danny Roddy’s recommendation of orange juice or Travis Culp’s recommendation of soda!
But for others, speed of glycogen replenishment is hardly likely to be the parameter to optimize. There are unlikely to be significant benefits for non-athletes from replenishing glycogen 6.5% faster, as was found in the muscle glycogen study [3].
Speedier glycogen replenishment is almost the only known benefit to fructose consumption. It’s possible that low fructose doses, about 9% of carb calories (perhaps 2-3% of total calories), may improve glycemic control. This is a lower fructose fraction than is found in PHD, and far below the fructose fraction recommended by Danny and Travis.
Given the known risks of fructose consumption, especially with chronic intake at high doses or in conjunction with polyunsaturated fats, it seems prudent to err on the low side. It seems to me that the Peat-atarians have failed to provide any evidence at all in favor of a higher fructose intake than is provided by the fruits, berries, and sugary vegetables recommended by the Perfect Health Diet, save for athletes in the midst of a race or post-race recovery.
Good post, I learned a lot from it. But just how relevant is what athletes happen to do to what is actually best to do? Unless these sports products were made based on available evidence then they don’t do much to make a point. I don’t trust athletes any more than I trust doctors, I don’t trust anyone. People are highly fallible, and health science is the worst I have ever seen.
But the central point seems to be valid. Although some fructose is clearly desirable for an endurance athlete, that doesn’t warrant the recommendation for the bulk of carb calories to be sucrose.
Cheers!
I think much of this needs to be put in greater context. The data listed above is only loosely associated with the reasons Peat recommends fruits to begin with. He recommends sucrose as a supplement when fresh fruits are unavailabl as well. Add to that fruits are great sources of salicylates and inisitol, two favorable nutrients for inflammation and insulin sensitivity. Peat on the whole suggests that if there were an “ideal” macronutrient ratio it would be 33% from each source, but would vary based on the individual’s response.
Some of the reasons Peat recommends sugar from fruit is because it leaves less for gut bacteria to feed on, it replenishes glycogen best, which in Peat’s view increases the liver’s capacity to detoxify the body of PUFA and excess estrogen, suppresses adrenalin and cortisol (stress response; of course paired with adequate protein and salt in the diet), it also stimulates the production of cholesterol, which if one thinks the cholesterol-heart hypothesis is bologna, would stand to bring up the protective effects of lipoproteins and their ability to bind endotoxin. I’m not a Peat expert but the above are just a few reasons he advocates fruit. My advice, start reading his articles because I feel his ideas regarding thyroid, stress, and hormonal status marry well with your ideas.
Don’t want to defend peat to much as people can make there own conclusions and read his work for themselves but this post isn’t really a fair critique of peat. The reason(one reason) why he thinks fructose is superior to glucose is its ability to promote liver glycogen storage, in a stressed state the body has a decreased ability to store liver glycogen and has to waste energy to create it. I suggest checking out his article on Glycemia, starch, and sugar in context, a critique of that would me much better. Also Ray Peat’s approach is based on a lot of things and has many factors, focusing on one part without looking at the whole won’t get you anywhere when it comes to his work.
Some random articles-
Fructose and dietary thermogenesis.-
“Fructose ingestion induces a greater thermogenesis than does glucose. This can be explained by the hydrolysis of 3.5-4.5 mol ATP/mol fructose stored as glycogen, vs 2.5 mol ATP/mol glucose stored. Therefore the large thermogenesis of fructose corresponds essentially to an increase in obligatory thermogenesis”
http://www.ajcn.org/content/58/5/766S.short
Sucrose ingestion normalizes ADX rats-
Adrenalectomy (ADX) changes CRF and NE activity in brain, increases ACTH secretion and sympathetic outflow and reduces food intake and weight gain; all of these effects are corrected by administration of adrenal steroids. Unexpectedly, we recently found that ADX rats drinking sucrose, but not saccharin, also have normal caloric intake, metabolism, and ACTH. Here, we show that ADX (but not sham-ADX) rats prefer to consume significantly more sucrose than saccharin. Voluntary ingestion of sucrose restores CRF and dopamine-beta-hydroxylase messenger RNA expression in brain, food intake, and caloric efficiency and fat deposition, circulating triglyceride, leptin, and insulin to normal. Our results suggest that the brains of ADX rats, cued by sucrose energy (but not by nonnutritive saccharin) maintain normal activity in systems that regulate neuroendocrine (hypothalamic-pituitary-adrenal), behavioral (feeding), and metabolic functions (fat deposition).
http://www.ncbi.nlm.nih.gov/pubmed/11415998
Dietary supplementation with n-3 fatty acids may impair glucose homeostasis in patients with non-insulin-dependent diabetes mellitus.-
“The blood glucose concentration tended to increase during MaxEPA treatment, and to decrease during the placebo period, the changes under the two regimes being significantly different (P less than 0.01). In addition, the rate constant for glucose disappearance (k value) for the intravenous insulin-tolerance test, which reflected the peripheral insulin sensitivity, tended to decrease during MaxEPA treatment and increase during administration of the placebo, there being a significant difference (P less than 0.03) between the changes during the two treatments.”
http://www.ncbi.nlm.nih.gov/pubmed/2394967
O3 deteoriates glycemic response-
“Average blood glucose concentrations during the third week were significantly higher fasting (+ 15%, p < 0.01), and during the day at 1100 h (+18%, p < 0.001) and 1500 h (+ 17%, p=0.002) on PUFA than on the saturated fat diet."
http://onlinelibrary.wiley.com/doi/10.1111/j.1464-5491.1992.tb01748.x/abstract
Gabriel brings up some good points. Peat only recommends sucrose as a supplement in the context of a nutrient rich diet. Its a fruit based diet and as far as I have seen fruits have been associated with pretty much nothing but benefits in the health literature.
A couple quarts of milk and OJ with a egg yolk or 2 will provide you with just about every nutrient, add some liver or shellfish and it becomes extremely nutrient dense.
The 33% recommendation is probably old. Ray’s current line of thinking as far as I understand is that you should eat primarily carbohydrates to minimize PUFA but certain sources(butter, coco oil. ruminant fats) are fine in moderate amounts. He usually recommends around 80-120g of protein and the rest of your cals coming from carbs with fat added for taste(some people may need more fat depending on health circumstances). Its not a fat free diet though, probably 20-30% for the average person.
Cliff’s probably right and the upper range of 20-30% gets you close enough. Let me add that having a Peat discussion on a this blog is epic! Central to Peat’s arguments regarding physical degeneration and longevity are PUFAs and their destructive synergism with estrogen via the stress response and diet. One way to avoid any excess PUFA would be to consume more starch and sugars from fruit, potato, and rice (all recommended in certain amounts by Peat with an emphasis on fresh fruit). If you lowered fat intake and increased carbohydrate intake your body would produce some fats from the carbohydrates in the form of saturated fats. This would be protective as it would lower exposure to PUFA.
“Sugar” is just one small part of Peat’s ideas and in my opinion should be addressed properly, which I feel wasn’t done here. Of course Paul was mainly responding to Danny’s post. I feel if Paul and Ray got together for an extended discussion of their respective research it would culminate in a more unified view. They each have different strengths.