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Fasting Affects the Brain

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Re: Fasting Affects the Brain

#101

Post by rv-de »

ravenstine wrote: post #34

I sometimes intermittently fast for 24 hour periods, but recently I've switched to skipping breakfast, which effectively works out to be a 17 hour fast for me if I eat dinner at 6pm and have lunch at 12pm. Everyone says it's the most important meal of the day, but I haven't found convincing evidence of this(especially that which isn't sponsored by grain and sugar producers), and not having a huge insulin spike at the…

> my sex drive has plummeted to near-zero.

you write that you started this regimen "recently". possibly your body is still adapting to it. initially the effect is weakening to some extent. after a while - provided a healthy diet and body - this should change and make you feel stronger and more vital.

Re: Fasting Affects the Brain

#102

Post by rossenberg79 »

mcfunk wrote: post #71
Goronmon wrote: post #59

Earlier quoted context omitted.

Fasting combined with exercise sounds like a recipe for overeating after the fact.

Once the body gets habituated to using fat stores for energy rather than glucose or glycogen, there's no particular need or urge to eat after exercise.

What if you are low on fat stores?

Re: Fasting Affects the Brain

#104

Post by phonypc »

rossenberg79 wrote: post #102
mcfunk wrote: post #71

Earlier quoted context omitted.

Once the body gets habituated to using fat stores for energy rather than glucose or glycogen, there's no particular need or urge to eat after exercise.

What if you are low on fat stores?

Define low.

Unless you're a competitive body builder on show day, you've probably got enough fat to cover a few weeks worth of energy needs.

Re: Fasting Affects the Brain

#105

Post by username444 »

new2626 wrote: post #83
ergothus wrote: post #72

Earlier quoted context omitted.

> Why would you wish such a thing? Being hungry and then eating is one of the nicest things in life. "hunger is the best sauce" - yes, I agree. Several years ago, I even made a similar comment to yours when I discovered a coworker disliked eating. But that was 50 pounds ago and I was overweight then. Now I find that a lot of pleasures of the world are less pleasurable because I'm fat. Eating less (and appropriately,…

Thanks for the response! Still, I wonder what we as society get so wrong. People used to eat whatever they wanted (and was available) whenever they wanted and not be fat. I recently watched the original woodstock 69 footage. There are zero fat people there. For all I know it may have nothing to do with eating.

There's a big difference between "eating when you want" and having an active lifestyle that restricts eating naturally, versus binging TV on the couch with junk food 10 feed away.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102055/

Conclusion

Over the last 50 years in the U.S. we estimate that daily occupation-related energy expenditure has decreased by more than 100 calories, and this reduction in energy expenditure accounts for a significant portion of the increase in mean U.S. body weights for women and men

That's 3000 calories per month, or almost 10 lbs of fat per year.

Re: Fasting Affects the Brain

#106

Post by beagle3 »

wyldfire wrote: post #27
mcfunk wrote: post #20

Earlier quoted context omitted.

I'll be interested to see where the scientific consensus is in 10 years. I think the evidence is very much on the side of the hormonal theory of obesity and fasting, especially given the monumental failure of the "calories in calories out" model.

> especially given the monumental failure of the "calories in calories out" model. Can you explain this in more detail? CICO seems like it might oversimplify things but it always seemed like a really sane basis for helping shape your diet. If you need to lose weight, you should plan meals to create a calorie deficit. But yes, I would not be surprised to learn that fasting on day X and consuming double your normal cal…

CICO is only true in a useless sense. Do you know how much energy you are putting in? Paper (cellulose) is carbohydrates, but not used by the body; gasoline is more energy dense than fat (at 12kcal/gr) and still unusable by the body....

So, it obviously isn’t just “carbs time 4k/cal”. Ok, let’s assume we can tell which carbs are useful and which aren’t. It takes energy to extract that energy. How much? IIRC there is over 50% variation between people (and even same person at different time) of the amount of energy actually extracted - yet almost everyone uses 100year old Atwater factors as if they were a fundamental physical constant.

Glucose storage is supply based. But gluconeogenesis (conversion of protein to glycogen) is demand based, so you must be at a deficit for the 4kcal/gr protein measure to be used.

How about body temp? A person at 35.6C uses a few tens or hundred calories less per day than a standard 36.7C person. Yes, these exist. Did you take this into the CO equation?

Did you consider the liter of ice cold water you drank? Takes 37kcal to warm it up to body temp.

CICO as usually practiced has 20-30 margin of error, which makes it much less useful than people assume. Unsurprisingly, it does work for e.g. 70% of the people, who assume the rest are not properly counting.

Re: Fasting Affects the Brain

#107

Post by beagle3 »

AnIdiotOnTheNet wrote: post #99
mcfunk wrote: post #64

Earlier quoted context omitted.

There's also good evidence that people don't maintain that weight loss over time despite maintaining their lower calorie consumption. Because base metabolic rate is something that the body can adjust, just like if you had less money to pay for heat, you could just put less heat into the house. The role of hormones (especially insulin) in regulating fat storage and whether stored fat is available to the body as energy…

> Just look at all the massive success of those in the IF and keto community in living joyful lives I'm not convinced most of those evangelists have actually lost and kept off significant amounts of weight, and nearly everything they say reads like a sales pitch so I'm not inclined to trust it. > Also "it's nice to believe you don't have to suffer to reach your goals" is a silly and moralistic thing to say. But it ty…

Somehow, among weight loss subreddits, /r/keto (and more specialized cousins) and /r/fasting stand out with a lot more success by average people who aren’t trying to sell anything.

Keto and fasting are fighting an up-hill battle: the only thing you can sell is guidance, and that is freely available. The keto bar/additive industry is minuscule.

Re: Fasting Affects the Brain

#108

Post by beagle3 »

SketchySeaBeast wrote: post #35
mcfunk wrote: post #20

Earlier quoted context omitted.

I'll be interested to see where the scientific consensus is in 10 years. I think the evidence is very much on the side of the hormonal theory of obesity and fasting, especially given the monumental failure of the "calories in calories out" model.

> especially given the monumental failure of the "calories in calories out" model. I don't think that's the case at all - do we have examples where people, strictly observed didn't lose weight when eating under their caloric requirements? There absolutely is a pile of mitigating factors in how someone eats or lives, but that's like saying "exercise has been proven to not help people run marathons" just because most p…

There is a serious problem with counting both in and out calories, to the point that makes this useless in general - e.g. in serious studies they lock you in a room with controlled air and temperature in order to measure carbon out (or fit a respiration mask to do that). Anything less involved has error in the tens of percents.

Furthermore - on phone now, can’t find ref - but mass general IIRC had a study where people where being significantly over fed (with a feeding tube) yet lost weight; google Robert Israel and Michel Cabanac for more info.

CICO is an often useful approximate description - but it is not (other than tautologically useless) a law.

Re: Fasting Affects the Brain

#109

Post by beagle3 »

Zaak wrote: post #49
Tharkun wrote: post #26

Earlier quoted context omitted.

Grandparent is talking about religious fasting, not a diet. It's likely not about calories.

Indeed. It's abstaining from all food and drink for a goal of 24 hours. I generally manage about 12, but it's something I'm working on improving.

Do note that almost everyone else only abstains from food, but does drink a lot of water (often with electrolytes). It makes a huge difference, irritability and otherwise.

Re: Fasting Affects the Brain

#110

Post by robodale »

ravenstine wrote: post #63
UpperBodyEimi wrote: post #38

Earlier quoted context omitted.

“Breakfast is the most important meal of the day" was an advertising slogan for Kellogg's.

The saddest part of that is that I heard that phrase not through overt advertising but from school . I remember a handful of occasions in elementary school where they had someone come in and teach kids about nutrition, and the one lady told us that breakfast is the most important meal because we need to start off our day with "lots of energy". These lessons included the food pyramid, which is bad science to start wit…

The Simpsons have parodied corporate-sponsored education for years: https://www.youtube.com/watch?v=zR_4h5A5z_A&t=1s
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