The FastDay Forum

What percentage daily should carbs be? If protein is 15% it seems, does that mean fat should be 50% and carbs 35%?

You just have to have emptied your glycogen stores sufficiently - then you seem to be able, in fact required, to refill with carbs. Low carbing looks to make sound sense up to the point where exercise becomes fairly strenuous but even Peter Attia takes in carbs to replace glycogen used in exercise (and repair muscle damage). I suspect true low carbing requires a sedentary lifestyle...

I'm not sure, my blood glucose level is the same as anyone else outside of the post-meal period.

Peter Attia seemed to be saying that by using more fat (as a consequence of adaptation) the depletion of glycogen is reduced anyway. I just walked for 55 mins at 3.7 mph with heart rate around 110-120 so I don't think much glycogen was harmed in that exercise.

What percentage daily should carbs be? If protein is 15% it seems, does that mean fat should be 50% and carbs 35%?

It has to add up to 100% so "yes", but that wouldn't count as low carb.

Low carb is more likely to be 60F / 35P / 5C with variations, some do less protein and more fat, others have perhaps 10% carbs.

Thanks Phil. Just found a paper
http://journals.cambridge.org/download. ... a/userPdf/
that had recommended protein 15%, carbs 45 to 55%, fat 30 to 40% for Optimal composition of diet for the metabolic syndrome using high fibre/low GI carbs.
How do I do links on my iPad please? (Out of my depth here!)

Pete: Since I have done only light exercise while low carbing I can't speak from personal experience. However, there are many world class athletes who low carb and are able to perform. I know of biathletes, cross country skiers and tennis players who eat ketogenic or near ketogenic diets. Also, Dr Attia speaks briefly about how this works in some of his lectures. It is an incorrect assumption that the body cannot perform while in ketosis.

I have read that there are situations where performance is improved with glycogen being used, but the examples were extreme and nothing ordinary people are likely to come across in a lifetime. I don't recall exact details but we are talking about a few percent improved performance during a marathon under special circumstances.

Thanks Phil. Just found a paper
http://journals.cambridge.org/download. ... a/userPdf/
that had recommended protein 15%, carbs 45 to 55%, fat 30 to 40% for Optimal composition of diet for the metabolic syndrome using high fibre/low GI carbs.
How do I do links on my iPad please? (Out of my depth here!)

no idea - executive jewellery
cut & paste (can iPads do that yet ?) the title and I'll find it.

actually I think I figured it out :-

British Journal of Nutrition (2000), 83, Suppl. 1, S143–S148
Dietary treatment of the metabolic syndrome – the optimal diet
Gabriele Riccardi* and A. A. Rivellese
Department of Clinical and Experimental Medicine, Federico II University Medical School, Naples, Italy

http://www.ncbi.nlm.nih.gov/pubmed/10889805

that the one ?? He concludes :-

Properly designed intervention studies with an adequate sample size should be undertaken in order to evaluate the clinical benefits of an appropriate nutritional approach to treating the metabolic syndrome, possibly as compared with the multi-pharmacological approach presently adopted by most physicians. Unfortunately, for various reasons nutritional studies are not easily funded by either the food industry or institutional bodies. In the absence of clear scientific evidence, individuals with metabolic syndrome will continue to be treated with multiple drug prescriptions that mitigate the symptoms, but are inadequate to treat the disease.

[carorees]

How does this optimal diet fit with Attia's diet of 90% of cals from fat? or are those figures of 45-55% referring to weight rather than calories?

the "optimal" (sic) diet is a bit off-topic it arose from a question about the macros but isn't Attia's diet. It's a review paper.

[carorees]

Yes I get that but I wondered why that particular balance is "optimal" and why Attia has gone for a higher fat percentage, but I also get confused when the proportions of macronutrients are quoted as to whether they refer to % of calories or % by weight.

Thanks Phil. Just found a paper
http://journals.cambridge.org/download. ... a/userPdf/
that had recommended protein 15%, carbs 45 to 55%, fat 30 to 40% for Optimal composition of diet for the metabolic syndrome using high fibre/low GI carbs.
How do I do links on my iPad please? (Out of my depth here!)

no idea - executive jewellery
cut & paste (can iPads do that yet ?) the title and I'll find it.

actually I think I figured it out :-

British Journal of Nutrition (2000), 83, Suppl. 1, S143–S148
Dietary treatment of the metabolic syndrome – the optimal diet
Gabriele Riccardi* and A. A. Rivellese
Department of Clinical and Experimental Medicine, Federico II University Medical School, Naples, Italy

http://www.ncbi.nlm.nih.gov/pubmed/10889805

that the one ?? He concludes :-

Properly designed intervention studies with an adequate sample size should be undertaken in order to evaluate the clinical benefits of an appropriate nutritional approach to treating the metabolic syndrome, possibly as compared with the multi-pharmacological approach presently adopted by most physicians. Unfortunately, for various reasons nutritional studies are not easily funded by either the food industry or institutional bodies. In the absence of clear scientific evidence, individuals with metabolic syndrome will continue to be treated with multiple drug prescriptions that mitigate the symptoms, but are inadequate to treat the disease.

Yes that 's the one. Have ideas changed much in the last 13 years? I was wondering whether equal ratios of c/f/p might be a better balance then, though isn't high protein now a cancer worry? Too much information can confuse too!

Yes I get that but I wondered why that particular balance is "optimal" and why Attia has gone for a higher fat percentage, but I also get confused when the proportions of macronutrients are quoted as to whether they refer to % of calories or % by weight.

The "optimal" thing is entirely in the eye of that author, in my view. It's a review paper - not my favourite type, one up on epidemiology - and reviews a range of middle to high carb diets. To my mind he ends up saying "we need RCTs to find out what is the optimum".

Attia is after "nutritional ketosis" hence much less carbs. Beyond about 35% protein is pointless hence it's high fat.

The percentages are almost always % of calories. There is a ratio from Sweden - Skaldeman - which is grams of fat per gram of protein.

Caroline – Many thanks for the refs and further info on metabolic inflexibility, all very interesting. From looking at your links plus the this one on “Metabolic flexibility in the dev of insulin resistance and T2D; effects of lifestyle, http://ki.se/content/1/c6/07/80/41/Geor ... frence.pdf I concur that there are probably more people than “a small minority” on here who are metabolically inflexible.

[quote="carorees"] Those who exercise regularly may still be metabolically inflexible as Peter Attia describes...if you exercise at a moderate intensity most of the energy comes from glycogen anyway. His self-experimentation showed that, before he adopted a ketogenic diet, glycogen was his main fuel, even though he was extremely fit.


I don’t recall Attia describing this. There may be some exercising folks (genetically predisposed?) who are metabolically inflexible but my view is that the majority of folks who exercise lower their RQs and become less insulin resistant. If you’re exercising at moderate intensity you’re relying on fat as the primary energy source not glucose, http://onlinelibrary.wiley.com/doi/10.1 ... 052431/pdf.
I don’t think his self experimentation showed that glycogen was his main fuel before he adopted a ketogenic diet. He referred to the fact that he was a marathon swimmer and that he would use a lot of supplementary gels/CHO sources. I very much doubt that a marathon swimmer relies on glucose as their primary energy source, I think way more likely it will be fat supplemented with glucose as per other endurance athletes. His use of gels etc I think came from the standard view in endurance sport that if you want to perform optimally you need to keep your glycogen stores well maintained as although fat is the primary energy source the athlete is still burning a combo of fat and glucose. I don’t think that’s the same as saying glycogen was his main fuel before adopting a ketogenic diet, but maybe I’m wrong ?

Staying on the subject of his feeding during exercise, I did find his comments in the qus section of the talk very interesting. I noted that he mentioned that:
On rides up to 3hrs duration the only food supplement he took was branch chain amino acids/protein. He also stated that if he wanted to ride at his best for up to 3hrs he would eat.
Rides over 3hrs he did supplement his glycogen stores with slow releasing carbs that wouldn’t effect his fat metabolism.
When he was on his IF+ intermittent ketosis diet he could ride up to 6hrs on only water.
I liked his mention of the 3 hr mark. I too don’t like to take any supplementary food on rides less than 3hrs, a view I've held pre and post starting 5:2. For me when going longer then 3hrs life gets pretty miserable without gels fuel etc. I also hold the view that if you really need supplementary food when exercising you’re doing it for too long.

I also found his comments on his perceived improvements with altitude training on a keto diet interesting. Would like to see some real research in this area.

Would also be interested to know what his wife and daughter think about his breath?

Now time for my 2 hot humid hours on the bike on a fasting day. Ketones prepare to saddle up...

http://www.uni.edu/dolgener/Advanced_Sp ... dation.pdf shows trained athletes with RQs in the 0.95+ area on bikes.

Endurance trained athletes were found to burn much more fat at medium work rates in http://link.springer.com/article/10.100 ... 006-0290-x

http://www.jappl.org/content/91/1/115.short looks specifically at fat adaptation in exercise.

Maybe also of interest, his latest Ted Talk
http://www.ted.com/talks/peter_attia_wh ... betes.html

Abby

[carorees]

Great talk, thanks for posting the link, Abby. It is interesting to view obesity as the result of insulin resistance rather than a cause and fits rather nicely with the paper I posted a link to about metabolic flexibility and insulin resistance. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2678135/ which posits that insulin resistance is a protective mechanism but which if too high leads to metabolic syndrome.