Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Fasting Affects the Brain

brainfacts.org

Post reply on HN
Print view View original

91–100 of 135 posts

Re: Fasting Affects the Brain

#91

Post by magnamerc »

ohaideredevs wrote: post #79
magnamerc wrote: post #24

Earlier quoted context omitted.

I've done 7 day water fasts (I try to do them quarterly, or bi-annually) and I find by day three I'm full of energy to the point where I have a hard time sleeping. I'm also way more productive during those 7 days. The only thing that tends to suffer is my weight lifting. I drop in strength a tiny bit, but not nearly as much as you'd expect. I also drop about 5-10 lbs in mass, with about half of that coming from water…

Being hungry increases alertness. This is discussed in "The Willpower Instinct", in the context of keeping you from sleeping well. It's natural - the body knows it needs to find food, so it makes you hyper until you do, negatively affecting the ability to get essential sleep. So, there is nothing weird about what you are experiencing - it's like wanting to get air when you are under water. Doesn't make it a good way…

Yeah I'm aware of the biological reasons for why I feel the way I do when I fast. There's a lot of science backing why fasting is good for you, and it has to do with mTOR and the science behind apoptosis, for which Yoshinori Ohsumi won the nobel prize in 2016. Fasting isn't a 'trend' like say 'cleansers' are a trend. One is backed by science, and the other is just a catch phrase to sell products to people.

Re: Fasting Affects the Brain

#92

Post by kemiller »

coldtea wrote: post #76
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.

It's only considered a "monumental failure" by people peddling this or that alternative diet. On the regular medical world, there are just new inputs about things that also matter, as science and our understanding progresses (as opposed "the calories thing is wrong, let's throw it out altogether").

The calories thing is wrong in the context of telling people to count them. In practice it is very hard to know exactly how many calories are coming in or going out in real life situations. Even labeled boxed foods are often way off from their official calorie numbers, and it’s not like most people are running their poop through a crucible, or doing all their exercise in a tank of water to measure their heat output.

Re: Fasting Affects the Brain

#93

Post by ohaideredevs »

magnamerc wrote: post #91
ohaideredevs wrote: post #79

Earlier quoted context omitted.

Being hungry increases alertness. This is discussed in "The Willpower Instinct", in the context of keeping you from sleeping well. It's natural - the body knows it needs to find food, so it makes you hyper until you do, negatively affecting the ability to get essential sleep. So, there is nothing weird about what you are experiencing - it's like wanting to get air when you are under water. Doesn't make it a good way…

Yeah I'm aware of the biological reasons for why I feel the way I do when I fast. There's a lot of science backing why fasting is good for you, and it has to do with mTOR and the science behind apoptosis, for which Yoshinori Ohsumi won the nobel prize in 2016. Fasting isn't a 'trend' like say 'cleansers' are a trend. One is backed by science, and the other is just a catch phrase to sell products to people.

The question is of balance. For example, if fasting keeps you from sleeping, I consider it an issue. If fasting causes muscle loss, I consider it an issue. I read the cancer research - how much is damage is being done by not getting the nutrition you need though? It's still a trend - there is no balance defined.

Re: Fasting Affects the Brain

#94

Post by dfawcus »

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…

It rather depends upon what one has for Breakfast.

I'll have a quarter pound steak (sirloin or ribeye), with veggies at 7am, and then not eat again until 6-7pm, when I'll have something light (say salad).

No lack of energy during the day, no cravings. However this does tend to mean that one is largely running on burning fat during the day.

Re: Fasting Affects the Brain

#95

Post by magnamerc »

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…

I used to be firmly in the CICO camp, with the whole 1st law of thermodynamics as a sane argument. But I've recently changed my views on this. If you think about it, the human body doesn't have a 'calorie sensor'. All it has are nutrient sensors, and cells metabolize nutrients depending on the current metabolic environment, which includes proteins and hormones for example.

Re: Fasting Affects the Brain

#96

Post by dragontamer »

Reedx wrote: post #66
tw1010 wrote: post #46

Earlier quoted context omitted.

That sounds plausible (and interesting) but do you have a source for it?

https://youtu.be/9Ffceu672c4?t=173 Dr. Kellogg and his brother had a business creating various supposed health products and Corn Flakes was part of that. In 1917 a magazine called Good Health, edited by Dr. Kellogg, wrote "in many ways breakfast is the most important meal of the day". That seems to be the origin and cereal makers ran with it.

> Dr. Kellogg and his brother

More importantly, Dr. Kellogg and his brother started two rival companies. The brother believed that sugar should be added to the formula Dr. Kellogg has been using to treat his patients.

Dr. Kellogg refused, believing sugar to be awful for the body.

Needless to say, we all know which of the two rival companies became the corporate giant, and which of the two rival companies disappeared into history. There was a big court case between the two rival brothers over the "Kellogg" name. After that, the two brothers never talked with each other for the rest of their lives.

https://en.wikipedia.org/wiki/John_Harvey_Kellogg#Breakfast_...

Since the two were brothers, it is somewhat ambiguous to who really invented modern cereal. But Dr. Kellogg was the health-fanatic who would have been studying "healthy breakfasts" and other such stuff.

EDIT: It should be noted that 1890s / early 1900s medical science was downright awful. So definitely take any health claims from that era with suspicion. Be sure to look up "sanatoriums" and how awful their medical practices / beliefs were. There's probably a nugget of truth somewhere in Dr. Kellogg's research, but you've gotta look at his claims through the lens of history to really understand him.

Re: Fasting Affects the Brain

#97

Post by ravenstine »

simonebrunozzi wrote: post #89
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…

> The only negative effect I'm having is that my sex drive has plummeted to near-zero. Wondering why this happens. Any idea?

My hypothesis is that, when the body is in a survival or self-repair mode, libido is placed on the backburner because it's just not that important to individual survival. If the body isn't seeking food, reproduction takes a higher priority. Someone else here was talking about how it might be related to a low body fat percentage, which would play into this hypothesis, and I am a fairly skinny guy(not scrawny or lanky, though).

Re: Fasting Affects the Brain

#98

Post by qntty »

coldtea wrote: post #78
qntty wrote: post #31

Earlier quoted context omitted.

This article makes a case against a calorie-centric approach to dieting. It boils down to something like Michael Pollan's "Eat food, not too much, mostly plants." A guy (who has since become an expert in public health) wasn't able to control his weight using standard calorie-counting techniques and had a lot of success changing his diet to "high quality" (as opposed to "highly processed") food. The article isn't supe…

People self-report they did "all the right things" and when checked found out they undercounted, cheated, etc all the time. In fact, the article says "He kept to low-fat, low-calorie food for three years. It simply didn’t work. At one point he lost about 10kg but his weight rebounded, though he still restricted his calories." Keeping a diet like low-carb or low-fat etc (and other fads), is difficult, so many rebounce…

Right. It seems like the issue is that "calorie in/out" means different things to different people. For some people it refers to the simple fact that humans are subject to the laws of thermodynamics. For people trying to lose weight, it refers to diets which are structured around counting your calories.

It's hard to doubt that lowering your calories consumed will cause weight loss. However, it's not obvious that the physical mechanism behind weight loss in itself provides enough structure for people to use as a practical tool for weight loss.

It's like if someone is trying to pitch a faster baseball and their coach introduces them to the "conservation of momentum" strategy for throwing faster. The idea being that if you want to move the ball faster, you have to move your arm faster too. Well, duh, but it's not obvious whether this will help anybody. It might be the case that practical strategies for pitching faster never make reference to the principle of conservation of momentum. That doesn't mean that conservation of momentum doesn't ultimately explain why every different strategy works, but it doesn't make "conservation of momentum" a strategy all by itself.

"Eat high quality foods" may very well be a better strategy for losing weight than counting your calories. It might be easier and more healthy than calorie counting for most people. That doesn't mean that "calorie in/out" doesn't on some level explain why this strategy works (although, there might be good reason to doubt this in some cases, new research suggests that the interaction between gut bacteria and food are an important factor in how people respond to different diets). But the fact that "calorie in/out" explains weight loss doesn't mean that it needs to be the central concept in everybody's dieting decisions.

Re: Fasting Affects the Brain

#99

Post by AnIdiotOnTheNet »

mcfunk wrote: post #64
AnIdiotOnTheNet wrote: post #52

Earlier quoted context omitted.

Eh. the articles argument appears to be that even though nutritionists, physicists, and dieters all agree that eating fewer calories than you expend causes weight loss, it isn't easy for a variety of factors. No shit. The thing is, it is the simplest expression of what needs to happen, and there is no getting around it. I was once well north of the weight of the subject in the article and have since shed about half o…

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 typifies the american "scientific understanding" of weight loss.

Saying you can achieve your goals with less effort if you BUY NOW is even more american. Even if no one is asking you to actually pay money for a program, they're still shilling an idea.

Re: Fasting Affects the Brain

#100

Post by AnIdiotOnTheNet »

mcfunk wrote: post #90
coldtea wrote: post #81

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. Well, it's not just some fixed calorie amount they need to take for an eternity. It's the amount that corresponds to their…

LOL ok, so "eat a diet and time your eating in a way that promotes healthy hormone balance and use of fat as energy" is a silver bullet but "use our magic equations based on state of the art info from 1958 to calculate your daily food needs and all your food and exercise as numbers and if your equation balances you'll lose weight" isn't. Sure.

You don't need any magic equations. It's really much more simple than that: if you're not losing weight, eat fewer calories until you are.
Post reply on HN