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Comment by theli0nheart | Hacker News Reader

> Fasting is tremendously helpful to productivity. Nothing will hinder your performance like a huge meal in the morning (especially one high in carbohydrates)

This seems to be really getting popular. What's the science behind it? I'm curious if this is mainly anecdotal or if you did some research before jumping in.

My 2 cents: as an endurance athlete and student of nutrition, skipping breakfast seems like a bad idea. Those calories get burned and put to use relatively quickly, at least compared to a meal later in the day, like dinner (with the caveat that this does depend on your metabolism and when you're most active).

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I started skipping breakfast a while back after having a big dinner the night before and realizing I wasn't hungry. I felt better than if I ate just because it was "time to eat." Over time, I moved the threshold, and I don't eat breakfast, except for a shot of espresso. It feels much better.

Earlier, I had worked to cut out carbs at lunch (because they were making me sleepy in the middle of the afternoon). With breakfast being so simple, I have to make sure I have a healthy lunch (went out to eat and failed today), and then I don't stress too much about dinner. YMMV, but this system has worked really well for me.

As for the science, there's a lot of research, but no one really knows how all of our elaborate cellular machinery works. However, there seems to be some notion of the body being in "digestion" or "maintenance/repair" mode. Letting your body get into the latter mode seems to have some really good effects.

Update-- of course, yesterday my wife made amazing oatmeal raisin cookies. I have no need to buy junk at the grocery store, but put a plate of homemade cookies in front of me, and "game over, man".

Google "intermittent fasting studies" and you'll find plenty of information.

Of course, if you're an endurance athlete its probably bad to skip breakfast before a race or big training regimen.

I'm as skeptical of fad diets as anyone, but it seems like science is starting to back-up the notion that some fasting is good for weight loss (lower calories, kick-starts ketosis) and brain function.

And it seems to line up with common sense, considering our bodies evolved for thousands of years of food scarcity.

I'll have to read up on that before forming and opinion, but I wonder if this hinges on a person being overweight, or regularly consuming a calorie surplus.

Yes, but that's most of Americans you're describing

So right now I'm 63 hours into a fast, which I just decided to do on a lark. I've been intrigued ever since hearing an interesting podcast on fasting (https://tim.blog/2017/05/04/smart-drugs-fasting-and-fat-loss...).

At this stage, I have started to find mental things a little harder to do, but honestly its still pretty subtle and is pretty indistinguishable from the normal kinds of self pity I normally have when I sit down to complete some hard mental task.

Physical tasks are obviously a different story. But your mind doesn't seem to slow down much at all for a pretty long time during fasting.

I think that's the main thing I'll take away from this experience. Eating does not improve mental performance, at least not unless we're talking about a multiple-day timescale. I now believe that it may slightly degrade it, because your gut gets greedy for your that thought-fuelling blood. This is useful knowledge to have gained because so often I think "ooo, feel a bit dumb, better eat."

> Physical tasks are obviously a different story. But your mind doesn't seem to slow down much at all for a pretty long time during fasting.

I’m not sure i agree with this. Highly productive sessions always end with me feeling exhausted despite just concentrating intently for several hours. Doesn’t your brain already consume like 30% of your energy? It would really surprise me if your brain operated at full capacity after 2+ days of no calories.

The assumption you're making is that your brain gets no calories when you have no food. Every kilogram of fat on your body is 9000 calories just sitting there. Most of us have at least 10 of em, or 90,000 calories.

While it's definitely true that some things slow down to conserve energy, it seems like the brain isn't one of em. There are moments* now I feel I'm thinking considerably clearer than usual. The world just feels unbelievably quiet. And things are getting done.

*I don't want to sell it as if it's all sunshine and rainbows. So far, getting to sleep has been hell, and the hunger pangs at times have been pretty insistent. While the hunger seems to have gone now, I have a general feeling of physical frailty, including lightheadedness when I stand up, and occasional light nausea.

> The world just feels unbelievably quiet.

This is what I sense when my fast crosses 18+ hours.

Yeah you certainly get a taste of it pretty early, and I think that taste is what made me intrigued to keep going, but lets be honest that taste is pretty well spoiled by increasingly desperate hunger. But I've just hit ~87 hours now, and everything else bad that happens mentally in the 18-60 hour period gets noticeably nicer once you go beyond the 60-70 hour mark, which makes that quietness way more enjoyable. Slept like a baby for the first time since starting last night, which makes a world of difference. Being too hungry to sleep is a special kind of hell.

This confirms some stuff I'd read on fasting. I'd read somewhere that the main pain is associated with re-establishing a new steady-state in which you're getting all your calorie needs from eating your own fat instead of your stomach contents, but I wasn't really sure if that was just wishful thinking by brain-washed fanatics. Fasting is still a non-mainstream practice so it's kinda hard to find reliable sources of information on it. But this particular point seems to be 100% legit, at least in the experience of this sample of one.

Well, I am quite skinny—it wouldn’t surprise me to be more affected by fasting than most.

Interestingly, there's some suggestion that fasting does increase your intelligence, at least for a while (at least, as always, in mice): https://www.nytimes.com/2006/12/10/magazine/10section1C.t-1....

It's definitely anecdotal as-in based on my own personal experience.

I fast for a few reasons:

1. Breakfast is not necessary, so skipping this meal saves me time in the morning. I already gotta worry about getting ready, feeding the dog+antibiotics, taking him out to pee, etc... one less thing to worry about.

2. Fasting for extended periods while in a ketogenic state accelerate fat loss. (the primary reason I fast)

3. I have noticed performance benefits with skipping the meal. (the cherry on top)

Really excellent guide: http://burnfatnotsugar.com/intermittent-fasting.html

What do you mean breakfast is not "necessary"? No single meal is necessary, obviously, but why skip it?

> skipping this meal saves me time in the morning. I already gotta worry about getting ready, feeding the dog+antibiotics, taking him out to pee, etc... one less thing to worry about.

I really can't understand how you can put "getting ready" and feeding your dog above your own nutrition. Maybe you don't enjoy food the same way that I do. How do you not have 10 minutes to eat something in the morning? It just boggles my mind

> Fasting for extended periods while in a ketogenic state accelerate fat loss

Why not just eat 3 meals per day but smaller portions? Isn't that more sustainable psychologically (and maybe physically)?

Basically there's a lot of health benefits to intermittent fasting.

This video covers a lot of it quite well & links to sources. Longevity & Why I Eat Once Per Day: https://www.youtube.com/watch?v=PKfR6bAXr-c

Please correct me if I'm mistaken but your comment seems to rely on the assumption that it is not reasonable if someone chooses to not make 10 minutes of time for breakfast.

While I do not wish to state my position on the "making time for breakfast" matter, I do, however, wish to state that if you _are_ indeed starting from that assumption, you are not really trying to understand where the other person is coming from.

>I really can't understand how you can put "getting ready" and feeding your dog above your own nutrition.

>Maybe you don't enjoy food the same way that I do.

First, these are two separate thoughts, unless you have some confusion between 'proper nutrition' and 'enjoyment of food'.

Second, 'proper nutrition' and 'enjoyment of food' often conflict since what provides the best nutritional value to your body is not often aligned with what tastes the best.

I think the different between you and OP's position is that you see a link between 'nutrition' and the breakfast event. What's your reasoning for believing that breakfast is important with regards to your body's nutrition/health? Do you understand it to be of short-term (i.e. energy levels before lunch) or long-term importance?

Actually "proper nutrition" and "enjoyment of food" are closely related. Although our bodies are selfish. For example, we like sugar so much because it's good yet used to be scarce. Now we finally can get plenty of it, but our body gets greedy and we overeat it.

> Actually "proper nutrition" and "enjoyment of food" are closely related.

I don't think that is the case for the vast majority of people. If I would only eat according to my "enjoyment of food" I would probably only eat cake and chocolate.

I don't do that, of course, because I value "proper nutrition" for my body above my "enjoyment of food". I see relatively few people around me that would take broccoli over cake if they are eating for "enjoyment of food".

That's what I said in 2nd part of my comment. We still crave for sugar which was hard to get. And our bodies are greedy and abuse it. Yet historically it was needed for proper nutrition.

Broccoli may suck, but there are lots of tasty veggies. I love to snack on fresh carrots or cucumbers. Don't get me started on how tasty nuts or berries are...

For me, it's the opposite. Of course I enjoy snacks, but I'd rather prefer to eat something both tasty and healthy. I'd prefer carrots and hummus to a cake 99% of the time

> First, these are two separate thoughts

Sure they are, sorry for mixing them up. Food for me represents both. Eating an avocado toast in the morning both makes me happy and gives me energy that I will use until around 12-13

> Do you understand it to be of short-term (i.e. energy levels before lunch) or long-term importance?

Both: short term as in energy needed during the day, and long term from a psychological point of view. This is subjective, of course.

You've been socially conditioned to believe 3 square meals per day are vital, and that breakfast is the most important one. That's simply not the case. Once you start to remove that bias, you'll have an easier time understanding where I am coming from with my lifestyle.

I'm not choosing my dog's nutrition over my own. Rather, I find that skipping breakfast is a win for me for fat-loss goals as well as mental clarity, and has the pleasant side effect of saving me time in my morning routine.

Funnily enough, breakfast is kinda important for fat-loss. What you eat in the morning will be burned throughout the day. Meanwhile a significant chunk of what you eat in the evening is not going to be burned and will be stored in fat.

Eating a lot in a single go is not healthy either. Thus you do need several meals throughout the day. 3 seems to be rather good balance. Although I personally prefer 2.

> Funnily enough, breakfast is kinda important for fat-loss. What you eat in the morning will be burned throughout the day. Meanwhile a significant chunk of what you eat in the evening is not going to be burned and will be stored in fat.

Meal timing is pretty much irrelevant for fat loss. The amount you consume and expend in the long run is far more relevant. Unless you're a top-level athlete, meal timing is the wrong thing to focus on.

Not being most important, doesn't mean it's irrelevant. I'm not saying to focus on it alone either. But it certainly does play a role how our metabolism work.

For example, snacking throughout the day is worst. Your body gets used to easy food and you feel hungry all the time. What you need is longer stretches of a day without food to make your body take energy from body fat. So you definitely need good timing to avoid snacking but don't overload your system with massive meal.

If you eat sugar late, you will get calories, but miss the energy boost. Meanwhile in the morning you'd use it productively.

While calories balance ultimately is the goal, different ways to achieve it are harder or easier.

> You've been socially conditioned to believe 3 square meals per day are vital, and that breakfast is the most important one

Where I come from, dinner is considered to be the most important meal, while breakfast is just a quick snack to give you some energy to "last" until lunch :)

> mental clarity

Can you expand on this?

This has nothing to do with enjoyment of food; one can enjoy food without worshiping it, ritualizing it, or being a gluttonous. Someone who enjoys video games isn't under any obligation to devote time to it each morning.

Either way, your body isn't going to be negatively affected by a 3-7 hour delay in getting nutrients. Many people aren't hungry when they wake up, and coffee is pretty good at pushing that feeling off for a couple hours more. Eating breakfast every morning when you don't need it is a waste of resources.

>Why not just eat 3 meals per day but smaller portions?

Why do you care about 'meals'? What's a meal? Do you think you evolved to consume food in meals? Whether you eat 'meals' - and how many of them you eat - was never a relevant question.

> one can enjoy food without worshiping it, ritualizing it, or being a gluttonous

I didn't mention any of those? I'm not talking about eating a full English breakfast every day. My breakfasts rarely involve more than 500-700 calories.

> Eating breakfast every morning when you don't need it is a waste of resources.

And the same is true for lunch and dinner. I'm not sure what point you're trying to make.

> Why do you care about 'meals'? What's a meal?

Come on, there's no need to be so pedantic :)

Would you have liked it more if I said "Why not just eat 3 times per day but smaller portions"?

+1 on the fasting, say what you would like about the products that HVMN (formally nootrobox) sells, but they have an awesome blog that covers keto/ketosis and nootropics use in general.

Update: didn't link.

https://hvmn.com/blog/

As others have mentioned there seems to be a number of studies about the health benefits of itermittent fasting. (I really love big breakfasts though:-)

For me however I do it because I get less tired during the day if I wait until lunch before I eat. (Fasting completely seems to work even better but is less of an option after I got a family that wants me to eat dinner with them.)

As a fellow endurance athlete who has experimented with fasting I would say don't waste your time. While I do think the response to fasting is somewhat personal, for me the impact upon long-term fitness, work/life stress (cortisol) [1] and ongoing metabolism [2] is just too severe to be ignored.

[1] https://www.precisionnutrition.com/all-about-cortisol [2] https://www.outsideonline.com/2284636/scientific-case-big-br...

I am not an endurance athlete, and I wouldn't even consider myself a health nut, but I know that i wake up hungry, and if I don't eat something (usually a fruit and greens smoothie with protein power and almond milk), I get too hungry to focus on work. I've also noticed that since I got more rigorous about eating (drinking) breakfast, I don't get as hungry late at night. It's almost, anecdotally, like my body know it can expect fuel in the morning and doesn't spend the evening stockpiling.

If you're fasting to lose weight, then you're probably also calorie restricting at those other meals anyway, and so eating later in the day and taking the "food coma" into the afternoon is better for productivity than in the morning (for me).

I went through a phase of only eating lunch at 12pm - so I'd be fasting for nearly 24 hours daily (of course, tied alongside severe calorie restriction meant I was losing weight at an unhealthy rate). Whilst probably horrendous for me long-term, and raising quite a few questions about my general health, I felt fantastic doing that. Some days I even felt like just randomly running along the pavement I had that much energy.

So, there might be some science behind it, honestly not sure - but that anecdata does make it a compelling thing to try.

I've also heard a convincing argument that there's an evolutionary response to prolonged hunger akin to fight or flight response that enhances cognition to better enable us to find food.

The super brief science is that your nervous system is divided into two opposing parts - the sympathetic and parasympathetic nervous systems. These systems inhibit the other when the one is activated. Programming in particular activates and works better with the sympathetic "flight-or-flight" nervous system, while eating food (particularly heavy meals) will activate the parasympathetic "rest-and-digest" nervous system.

Plus, removing unnecessary breaks and decisions in your day can help too.

This will one day be as obvious as cigarettes cause cancer is.

Prolonged fasting (consuming only water for 10 to 40 days) is a highly effective treatment for many diseases, including Crohn's, most other IBS related, diabetes, MS, and many more. At some point in the future we will consider pharma companies, government agencies and other entities hiding this fact to be criminal.

Edit: my personal hope is that water fasting becomes mainstream and cures many people before my HN karma reaches 0.

Do you partake in any sort of sports? As someone who is avidly into strength training, I can't imagine the damage that does to gaining and maintaining muscle mass, and sabotaging your ability to push hard and perform well in the gym.

Yeah you would definitely need to take a break from strength training to do an extended fast. Not everyone's goals however are to get huge muscles and for many health goals there is a lot of research showing that fasting has great benefits. It's probably one of the best ways to lower your risk of cancer.

> Not everyone's goals however are to get huge muscles

I should point out that strength training != bodybuilding

As with so many things in health and nutrition, there is a lot of contradictory advice out there. I can't tell you which one is right, but I have heard many people say never skip protein, because you need it every 2 hours, and others say:

https://www.bodybuilding.com/content/intermittent-fasting-ev...

Intermittent fasting is certainly a whole different ballgame than the multiple-day water fasts described in the comment above

While I disagree with your assertions, if you are the type of person who prefers to live the rest of your life with, say, Crohn's, and be able to still push hard and perform well at the gym, by all means do that. If you're willing to set a side of period of a couple months to heal your body, research more.

It's actually interesting how many people I meet at the gym that from the outside appear very fit and healthy, only to find out they're actually pretty ill, from IBS and other gut issues, thyroid problems, etc. The gym is actually masking many diseases for people because physically they appear healthy.

>It's actually interesting how many people I meet at the gym that from the outside appear very fit and healthy, only to find out they're actually pretty ill, from IBS and other gut issues, thyroid problems, etc. The gym is actually masking many diseases for people because physically they appear healthy.

Any idea how that compares to the average population? I'll bet you'll find that the gym population is pretty much the same as the regular population, with the exception of possibly greater cardiovascular health.

I just take exception to treating a 40 day fast as some sort of panacea, it seems like it's going to do more harm than good to a lot of people. There's no way the rest of your life won't suffer after a couple of weeks of starvation.

A -lot- of bodybuilders do intermittent fasting (between 16-23 hours per day of not eating and do fine. I see that all the time.

But the ones who are doing the 10-40 day fasts are usually fighting some kind of disease from what I've seen. Sometimes it's a weight loss thing but I don't see that nearly as often. From what I've read/watched I doubt any of them are doing much working out.

Crazy enough the longest ever recorded fast was 382 days long. The patient was 456lb at start, ending at 180lb. They gave him yeast and vitamins during some parts but overall they reported no ill effects afterwards. I don't say this as a "jump in and go nuts", this person was under medical supervision, but it's really crazy what the human body can do.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2495396/pdf/pos...

I do 2-5 day water fasts, and it has very clear health benefits. There urgently needs to be more research into it, especially for autoimmune diseases (like the ones you mentioned), but I don't think it will cure those diseases by itself.

I've also done a lot of calorie restriction and ADF. It probably isn't for body builders, but my BMI is now normal and muscle tone is good.

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