Where does energy come from during a fast?

(Ellenor Bjornsdottir) #24

You capitalise data like it’s an acronym. It’s not. Don’t do that.

I’m just gonna say citation needed on what sort of “data” you mean and mute this thread.

(Bunny) #25

If your using muscle while awake your going to use more stored glycogen (glucose) even with simple daily tasks?

The brain of course will be powered by the liver but with more glucose than ketones, too much glucose and the brain will make fructose to give back to the liver which is strange?

(Bunny) #26

Do have any DATA to support what does not make “physiological sense,” you have to have a reason from somewhere and was wondering what your source of information is?

Phinney and Volek do not even know with all their research?

(Bunny) #27

Don’t ever tell me what do my friend!

#28

Wow, Vegan, record holding weight lifter that eats OMAD. Talks about autophagy and the importance of meal and exercise timing is important to his way of life. Relies on his body recycling his proteins to stay youthful. Very interesting.

#29

I agree with there being a very limited amount of research. I guess without food company funding, that makes it hard :slight_smile:

For a non-athlete such as myself, I think you are correct. I noticed for myself on a 7 days fast that I had energy to spare on day 3, but when I worked out again, I did a lot less 2 days later. Mind you, I didn’t discover that I needed to add salts so that was likely a factor. But I think that you’re right.

It looks like the story is different for athletes. The FASTER study mentioned above is concluded the following:

Compared to highly trained ultra-endurance athletes consuming an HC diet, long-term keto-adaptation results in extraordinarily high rates of fat oxidation, whereas muscle glycogen utilization and repletion patterns during and after a 3 hour run are similar.

I have a long ways to go. But I’ll just KCKO! :slight_smile:

(You've tried everything else; why not try bacon?) #30

I think a certain amount of muscle loss, simply from having less fat to haul around, would be healthy. Enough muscle loss to qualify as “wasting” probably wouldn’t be. Have you read the case report on Barbieri? I believe they measured some of this, but I lost the PDF in a computer accident and haven’t been able to find it online again.

(bulkbiker) #31

Was it this one?

(Doug) #32

Mark, I get an error for that link. Even the NIH link online does it.

https://pmj.bmj.com/content/postgradmedj/49/569/203.full.pdf

Paul, it doesn’t say much about lean tissue loss. When he was done fasting, he was fairly ‘normal’ but I have no idea how strong he really was. That’s wild, losing over half one’s weight. The legs and back would think it’s a whole new world.

(Polly) #33

Interesting and may be geographical, but Mark’s link works for me.

(bulkbiker) #34

Hmm both links work for me…

I’ll post this article which also has a link so you can see if that works.
Otherwise I can screenshot it and send it to you if you’d like?
M
https://cristivlad.com/total-starvation-382-days-without-food-study/

(Doug) #35

It works perfectly for me now, Mark. :partying_face: I wish we’d have another such fast, rigorously studied, today.

(You've tried everything else; why not try bacon?) #36

Yes, Mark, that’s it. Thank you!

(Elmo) #37

A 30 hour fast??

(Bunny) #38

His blood glucose hovers around the 30’s, this is just a shot in the dark but I wonder if that is what normal should be if you lowered the sodium.

Human body only needs 0.5 grams/500 mg. of sodium a day. Any more could be is toxic.

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(Jane) #39

So not eating for 30 hours caused your blood sugar to be permanently high immediately after that and never came back to normal for an extended period?

Or do you have a different definition of diabetic?

Sorry this happened to you - must have been scary.

(Doug) #40

If that’s our old buddy Angus, then yes - he really went along quite low for a long time. That one reading at 17…:smile: For fans of the other measure, that’s just under 1 mmol/L. :astonished:

Sensitivity to higher intake of salt only affects ~25% of the population. For the rest of us, barring kidney trouble or a few other things, it’s usually not a big deal, as long as we get enough.

(Bunny) #41

Everything I’m reading is giving me a strong sense or indication that high amounts of sodium not the chloride part is causing renal failure and contributing to diabetes which is a big thing with Native Americans.

You can make glass out of this stuff according to the Egyptian historical records (As described by Pliny The Elder). When mixed with Natron which is basically baking soda but nobody to this day can figure out how they did it.

(You've tried everything else; why not try bacon?) #42

The PURE study, and several others that came out around the same time confirmed it, showed that 4-6 grams of sodium daily is the healthiest range of intake, being the low point of the risk curve. Lower than that range, the risk curve rises quite steeply, above that range it rises, but not as fast. In other words, the risk curve is what they call J-shaped. In the case of salt-sensitive hypertensives, however, while the sweet spot of the risk curve is still the same 4-6 grams, the risk curve is U-shaped; in other words, the risk rises equally steeply below and above the healthy range.

Note that 4-6 grams of sodium represents 10-15 grams of table salt (sodium chloride).

(Doug) #43

Appropriate to this thread, and fittingly titled, Fuel Metabolism in Starvation

By George Cahill, and it says right upfront that it’s “partly biographical and partly scientific.” But there’s lots of good information. It starts getting really sciency on page 6. My own paraphrasing of some of it:

When fasting, nitrogen excretion goes way down (in obese people, anyway), meaning not much lean tissue is being consumed. The brain switches over to using mostly ketones for fuel, rather than glucose. This means that much less glucose is needed, and hence, much less lean tissue (muscle, etc.) breakdown.

a normal adult human could survive two months of starvation; an obese person could survive
much longer.

When fasting, ~40% of fatty acid metabolism in the whole body is from the liver making ketones.

After 2 or 3 days of fasting, the liver pretty much stops making glucose from glycogen. During longer fasts, the total glucose production - from any and all abdominal organs - is about 80 grams per day.

During longer fasts, the kidneys make ~40% of the glucose we use, the liver makes ~60%.

The increased fat breakdown during fasting releases fatty acids and glycerol - the liver uses glycerol to make glucose.

Higher ketone levels eventually slow down the release of fatty acids from our fat tissue - a counter-regulating effect. (This would probably be a ‘self-limiting’ factor that would apply to how much fat we can access per day, etc.) “but insulin is necessary for this effect.” I presume once again that this is an example of “lower insulin” being better for fat loss and energy production.

Ketones as a good fuel source - a working rat’s heart shows higher work output and lower oxygen consumption when it’s running on a mix of ketones and glucose, versus glucose alone. This is observed in other entities as well. Ketones are ‘ancient’ molecules that have been around and in use for billions of years. They’re a more efficient fuel than glucose.

Newborn humans are in ketosis. At birth, blood glucose levels go way down, and ketone concentrations rise, with the brain accounting for 60% to 70% of total metabolism - and almost half the brain’s energy is coming from ketones. Mother’s milk starts out with lots of triglycerides (fat) and protein, but not much sugar at all. Keto diet! This changes in the first few days, the lactose concentration increasing and the baby leaving ketosis.