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I recently read that Cochrane has been compromised, I take “Gold Standard” with a pinch of salt. I listened to an interview with Tim Noakes, author of “The Lore of Nutrition”, whose book promulgates a high fat low-carb diet. Weight loss and managing (reversing) diabetes are its salient features. He apparently went to the Supreme Court of South Africa to defend his position and won against “big food”. He was formally a high carb advocate. Looking forward to the next instalments.

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author

Cochrane has received some funding from sources that have compromised it to some degree, but in this particular review, there wasn't really anything to fudge - the evidence base for ketogenic diets in epilepsy is slender.

Stay tuned to Parts 3 and 4 as I'm covering weight loss and diabetes.

BTW, arguing for a diet that contains minimally processed carbohydrates in evolutionarily appropriate amounts is the very opposite of taking a pro-Big Food position.

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Wow, lot's of polysyllabic words in that one but I got to the end unscathed.

I've never been a fan of any sort of fasting and am even less so now after reading your lucid little essay. I'd rather lift some weights or use my resistance bands or do some hill sprints on my magnetic resistance exercise bike (and get o chow down into some cauli/carrot topping on sourdough wholemeal bread than fast.

Cheers.

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author

Hehe, congrats for hanging in there! I'm not agin fasting by any stretch of the imagination, but if you want to get the maximum available benefits out of it, you need to understand fasting physiology.

Resistance exercise is hugely important for extending one's healthspan and probably, lifespan.

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I like to sample the local wares ... two recent trips, Adelaide and Yeppoon, both had extremely moorish French bakeries ... the almond croissant diet is a favourite as is the newly discovered pistachio raspberry croissant.

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author

Definitely not my recommended form of carbohydrate intake ;-).

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founding

I have become quite interested in fasting, specifically intermittent fasting. I read Dr. Fung’s book, The Complete Guide to Fasting and he argues that muscle tissue is not broken down in the short fasting periods. When you reference a short fast, are you talking 3-5 days? Do you think intermittent fasting of 18/6 is a healthy benefit to someone who does not need to lose weight?

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founding

Thank you for your great posts! I appreciate your work.

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author

Thank you for reading!

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author

It's very obvious that muscle tissue is broken down in short fasting periods (3-5 days), because of gluconeogenesis.

Narrowing the eating window to around 8-10 hours (time restricted eating) does appear to have benefits for weight loss, especially if you practise early time restricted eating i.e. eating breakfast and lunch, but skipping dinner.

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founding

I very much appreciate you taking the time to respond to my inquiry. Metabolism is a very challenging process to understand and I am many years removed from when I studied it in my training. Intermittent fasting seems to be the 'hot topic' at the moment so I have started to study about it and why it is beneficial. But when reading your piece, I found conflicting information from what Dr. Fung writes in his book.

My two questions for you:

1. Does intermittent fasting have benefit for those of us not trying to lose weight? Perhaps you will cover this in an upcoming piece. Dr. Mercola, Dr. Fung,. Dr. Means , Dr. Marik and others rave about its benefits of reducing insulin circulation to promote autophagy and reduce the storage of fat.

2. Dr. Fung has a chapter dedicated to the myths of fasting and one of them is entitled "Fasting Makes You Burn Muscle". He cites a study from McCue, ed that demonstrated that alternate day fasting did not lead to loss of lean muscle. He goes on to say that muscle wasting from fasting would be maladaptive based on our history as hunter/gatherers. He says that muscle is not used for energy until body fat becomes so low that the body has no choice but to burn muscle (when body fat drops below 4%). Why would the breakdown of muscle tissue be favored over using stored fat for energy?

Again, thank you for your work and the time you take to help educate us!!

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author

1. I'm not intending to be pedantic here, but we need to be very careful to define our terms in order to avoid confusion or talking at cross purposes. I presume that the practice you're referring to is time-restricted eating (TRE), which Dr Marik has recommended as a way to upregulate autophagy. TRE is the subject of a lot of research at present, with contradictory results on weight loss. Satchin Panda's lab has pioneered the study of TRE, and their research has found benefits for circadian rhythm, including sleep quality.

2. Could you provide more detail for the McCue reference? The only study I've been able to find by that author is one done on mice: https://www.physoc.org/abstracts/direct-measurements-of-substrate-oxidation-using-13co2-breath-testing-reveals-shifts-in-fuel-mix-during-starvation/. The response of mice to food deprivation is somewhat different to that of humans. Regarding Dr Fung's hypothesis that muscle wasting from fasting would be maladaptive, as I mentioned in the article, accelerated body protein breakdown for the purpose of gluconeogenesis occurs for a relatively brief period near the beginning of a fast (when glycogen reserves are becoming depleted). Since the purpose of gluconeogenesis is to secure adequate supplies of glucose to fuel high-intensity physical activity (like hunting), as well as mental sharpness, it's not maladaptive at all.

Further thoughts on the role of insulin: lowering insulin secretion reduces muscle protein synthesis, since insulin, as mentioned in the article, is the body's primary anabolic hormone. This article https://www.frontiersin.org/articles/10.3389/fnut.2021.640621/full is an interesting read and confirms the earlier research that I cited on the metabolic adaptations to fasting: "AA [amino acid] oxidation is generally low after an overnight fast but can increase with the duration of the fast (i.e., up to 3 d) (37), which during a period of acute starvation would contribute to a negative whole body (61) and muscle protein balance (38)."

The studies cited in this article which demonstrate accelerated muscle protein breakdown in the early phase of fasting are https://pubmed.ncbi.nlm.nih.gov/1254728/, https://pubmed.ncbi.nlm.nih.gov/8017334/, and https://pubmed.ncbi.nlm.nih.gov/27245338/; the last study found that obese subjects have less muscle protein breakdown than lean subjects BUT they still had some muscle protein breakdown.

Thanks for your questions which help to clarify my thinking on this subject, and hopefully are of value to others too.

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Yes, that is interesting about muscle loss from short fasts. Intermittent fasting seems popular these days, that is restricting food intake to 6 hours or less per day, this seems to help me function better.

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author

Strictly speaking, that's time restricted eating, rather than intermittent fasting which refers to practises such as alternate day fasting and the 5:2 diet.

Narrowing the eating window to around 8-10 hours (time restricted eating) does appear to have benefits for weight loss, especially if you practise early time restricted eating i.e. eating breakfast and lunch, but skipping dinner.

.

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Agreed about the terminology. Time restricted eating equals less digestion, therefore more energy for other uses. For detoxing, a long fast seems to make more sense. If care is taken with the diet, then retoxing can be delayed and hence a longer time between fasts. A long fast would be a great time for colon housekeeping, keeping a clean one is essential for a long and healthy life. High fives for high enemas!

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