> Isn't that the whole point of fat storage, to provide caloric fuel when you don't have access to it through food?

The whole point is to use it as a last resort to not die. Not to just use it up when you could eat normally. And there are a lot of reasons why this is the case.

First, it's what the body and your brain wants, and they make you feel like absolute shit if you don't eat. What you weigh doesn't matter, starving yourself is really really hard, because every cell in your body is screaming at you to not do it.

Secondly, it's unhealthy. Part of that can be alleviated with supplements as you say, but the other part is that your body goes into survival mode when living off your fat reserves. Your body weakens, you health worsens, your immune system goes downhill, you have less energy, and some of these effects persist even after you start eating normally again.

And then there's the problem that such a crash diet, even if you go through with it, may make you lose weight, but it won't keep the weight off. Heck, you just taught your body that "sometimes there will be no food for 6+ months", and to that, the body responds "well, then I'm going to eat literally everything I can get hold of while we do have access to food". The body tries to repair the damage and recover the lost fat reserves. So you end up regaining the weight you lost, but with some additional permanent damage to your health and to your metabolism.

All because you had this idea in your head that literally anything, including month-long starvation, was better than being fat.

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I think your last statement is out of line. It's not really about being so detrimentally adverse to being fat, but rather that it would be easier to do nothing with the benefit of losing weight rather than managing a healthy lifestyle

The human body was "designed" to maximize survival in east africa where we evolved. Early humans, and all of our primate ancestors, would have often experienced periods with limited food and thus evolved means to store energy when food is plentiful and defenses against starvation when food is not. Both of these are systems that you need to prevent from working properly to loose weight, which from the body's perspective is bad, as it is loosing its defenses against starvation.

If you simply stop eating, biological pathways will engage to reduce your metabolic rate, deprioritize some repair, and neuro-chemically prioritize your brain to search for food among many many other things. The body is preparing to last as long as possible in "starvation might be coming mode" until food can be found. None of these help you lose weight as your body is trying to play the long game - in addition to you potentially doing damage to yourself if you're missing critical nutrients.

If you run a calorie deficient, slightly under what you need to maintain weight, your body doesn't enter the "prep for imminent starvation mode" that reduces weight loss. For some people with psychological or other extenuating circumstances, starvation methods may be required under medical supervision, but essentially it is never effective for the average overweight person.

Your body cannot convert fat back into usable energy in large enough quantities to survive. You will starve, even if properly hydrated and vitamin'd.

Your body burns fat to span the gap when you run a caloric deficit, so while "don't eat" is dangerous, "eat less" is in fact the only solution (excluding surgeries, for example).

Because your body uses fat reserves really carefully. All your body does is notice you're not getting any food and so it assumes there is currently a food scarcity. Your body will then start slowly burning your fat reserves so you still get some caloric fuel, but not as much as you would normally get when eating. This is because fat in your body is treated as a reserve, and therefore your body will ration it to prevent you from burning it too fast. This happens no matter how much fat you have stored in your body. Because of this, you risk burning too little calories and that can result in other problems.

And even if you endure all that without any problems and reach your ideal weight, your body will immediately start rapidly replenishing your fat reserves for when another food scarcity occurs. This will result in you getting a part of your weight back very quickly. And while your body is gaining that weight back, your daily available calories are still limited because your body needs to store that energy.

You need to realise that being overweight/obese is almost certainly closer related to mental health concerns than just purely consumption vs usage.

Eating is a coping mechanism, helps you deal with stress! Whether that stress is brought on by being overweight is irrelevant.

So when you try to lose weight without first addressing the mental health aspect, the entire exercise is fruitless.

So now, because you rob the brain of important endorphins released during eating, you're placing yourself under additional stress, which leads to further mental issues, which makes it even harder to be honest with yourself!

We don't understand all the ins and outs of mental health yet. We don't even know what depression really is yet! But we do see it manifest with eating disorders, one of which is excessive fasting like you're proposing here.

>Your body cannot convert fat back into usable energy in large enough quantities to survive. You will starve, even if properly hydrated and vitamin'd.

Isn't the point of Angus Barbieri that you can? Or do you think that case was a fluke/faked?

I'm skeptical, but I'd be open to seeing anyone repeat the stunt.

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As your body goes into starvation mode it doesn't burn fat, instead it uses protein from muscles for food and this can include the heart muscle, so a starvation diet even for a fat person can result in them dying of a heart attack even while they still have plenty of fat on them.

I mean, there are a whole buttload of reasons people are overweight other than mental health issues - I'd wager that the majority aren't caused by stress eating.

Poor food literacy, poor understanding of health, poor access to fresh food and an over abundance of processed/sugary etc foods in the modern Western diet are probably a much larger cause than stress eating.

I do agree with your underlying point, however, that without identifying which of these points is the persons issue and addressing it there is no way they are going to lose weight healthily and consistently

I have seen several long fasts, although nothing as long as Angus. More like a month. But I have no reason to doubt it, so I don't see why you would make claims that it cant be done.

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This is just my experience - I did aggressive IF fasts - 16 off/8on with calories consumed around 1000-1100. In my experience, the more you have to lose, the "safer" you can eat minimally as long as you doing some physical movement - like light weight lifting to keep your muscles active. You have to be careful as you will absolutely hit a brick wall and you have to start eating more to keep your body from crashing. Angus Barbieri had a lot of fat stored up and so he was able to go a long time without eating as long as you incorporate some sort of muscle resistance exercises. Since losing weight, I have to eat more as my metabolism is a lot higher and I'm way more active but it just gives me a little leeway to eat more. I still CICO as aggressively as I can.

Personally, I don’t think it’s typical at least. At the other end of the spectrum I’ve read about someone who died of starvation while still obese.

The problem is that there is no protein coming in, and burning fat isn’t going to contribute to your protein needs, so your body is going to catabolize muscle too. This includes your heart muscle. It’s common for anorexics to die of mitral valve prolapse or congestive heart failure.

I don’t know if my example or your example is closer to typical, but not a risk I would consider.

I also want to note that Barbieri died in his early 50’s. Wouldn’t surprise me if his extended starvation period resulted in a heart attack some years later.

Almost everything you said is wrong.

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I imagine the answer to op's question would be whether or not its healthy like you stated.

>At the other end of the spectrum I’ve read about someone who died of starvation while still obese.

Was this person in a trial where they were getting the necessary vitamins/electrolytes or were they just fasting on their own? And how long? I am curious but there doesn't seem to be a lot of studies like with Angus.

>The problem is that there is no protein coming in

I am pretty sure some of the supplements Angus was taking included amino acids.

> Why can't you just not eat if you're overweight?

For a while (even a long while!) you certainly can but your body comes with safety overrides (psychological and physical) which can override the will power most have.

Can you hold it if you have to go pee? Sure you can. But it will be unpleasant and eventually you will either give up or be tortured by your decision till you die.

If you have ample fat reserves and resist eating your death can take much longer but it's still inevitable and will not be pleasant.

A month is fine. A healthy person takes about 3 weeks to die with no food. A person with ample fat reserves would (or at least should) last longer.

Angus' feat was done with close supervision and (as far as anyone can cite) only once. I'm skeptical, as I said, and there's nothing radical about the idea of fat reclamation falling short of subsistence. I'd be curious to see someone replicate it.

In a "mentally healthy" human, the desire to eat goes away almost immediately after you start eating, and it doesn't come back for another 4-8 hours, so it's really difficult to consume more than you'd need without purposefully choosing to eat more. This is why I list it as a "mental health concern", specifically avoiding the word "issue".

I'm trying to distance the thought train away from the "practicality of just eating less", because it doesn't work that way anyway.

Poor food literacy and understanding of health usually relates to an unstructured upbringing or trouble at home, also raising a mental health concern.

There are also significant cultural considerations. In my country, for example, male obesity is highly regarded as a sign of success and abundance, and these men prefer "curvy" women - our per capita obesity is worse than USA, even though we don't have access to high fructose corn syrup at all, and we have a massive government imposed sugar tax, so almost nothing has sugar in it anymore!

Yes, except this has been debunked thoroughly and you should stop spreading misinformation.

Not claiming to be an expert on Angus, but wiki says he lived on “tea, coffee, soda water, and vitamins”. No protein/amino acids in most vitamins, although maybe they said vitamins when they meant supplements.

The obese starvation victim was mentioned in a scientific study I read. It’s entirely possible there was a link to another paper with more details but I didn’t follow it. I just recall reading that drove home for me the importance of protein while dieting.

From first paragraph on wikipedia:

> he consumed only vitamins, electrolytes, an unspecified amount of yeast (a source of all essential amino acids)

https://en.wikipedia.org/wiki/Angus_Barbieri%27s_fast

Sure, but I'm not asking about it as a plan or practice exactly, I'm more curious about the...I dunno, mathematics? Like as I understand it, a human being consumes a certain amount of energies in the form of calories, they use that energy to function physically in a variety of ways, and any surplus they have is converted into fat and stored in the body, any deficit is covered by using those fat stores. I'm assuming I must be misinformed about that, because it seems like consuming zero calories would mean that all energy requirements would be drawn from fat stores, so as long as you still had fat stores and consumed the vitamins and minerals needed to fuel the numerous chemical reactions that a human does, you shouldn't be in any danger, but everywhere I look says that simply not eating is inherently bad for you and doesn't explain how Angus Barbieri was able to accomplish it

What do you mean "burning too little calories?" Doesn't an activity require the same amount of calories whether it's coming from food or fat reserves? Like if someone eats and runs a mile, they'll burn more calories than if they didn't eat and ran a mile? How does a human body release less caloric fuel from fat reserves than it would normally take to do something?

Your body weight is mostly water.

You drink a liter of water, you gain 1 kilogram of weight.

You urinate 1 liter, you lost 1 kilogram.

When you're starving, your body functions slow down significantly, meaning you start to retain the water that you drink, so you don't lose weight like that..

But you still need to drink water and urinate, else your blood becomes toxic!

Of course, but once again, you're talking about weight loss, I'm just asking about the human body storing and using calories. Ignore weight in this scenario, it's not a factor. What I'm trying to figure out is why you'd go into starvation mode at all. In this scenario, the subject is taking supplements, a wide array of vitamins, minerals, amino acids, and basic proteins, and they're drinking plenty of water. So they're not suffering from malnutrition or dehydration. They're also obese and have many pounds of fat storage (Barbieri weighed in at 207 kgs at the start of his fast) so they aren't deprived of caloric fuel; why would they go into starvation? Why would any bodily function slow down when it has all the water, nutritional needs and calories it has to perform them as well as it needs? And even if they did go into starvation, they still have to consume calories, and the calories they consume have to come from somewhere. Would the human body really just die of starvation while being completely dietary supplied and with an ample supply of calories still available to it?

Starvation is triggered by hormones, which are released because your stomach is telling your brain it's empty and ready for more. This starts 4-8 hours after your last meal, always. If you interrupt these hormones, like some diet pills did, then you get "magic" weight loss without feeling bad.

But now you're damaging the brain, telling it to ignore basic survival signals - and the brain doesn't run on glucose, so it cannot get fuel from body fat - it needs your liver to create ketones from fatty acids, and when you consume fatty acids, you're adding calories again, which will allow you to survive indefinitely.

That makes sense. But it still doesn't explain the mysterious case of Mr. Barbieri lol I'm beginning to feel a certain amount of skepticism over the case now. Thanks for the input man

Doctors can keep people alive in comas for decades, we've got plenty of proof for that.

If your goal is to be "alive", then sure, it can be done using supplements and your body fat reserves - we've also seen a few cases of this.

The amount of permanent damage you do to your organs and brain, however, is unknown. How the extreme starvation feelings will rewire your brain is unknown. How your body will react when you start eating again is largely unknown.

Unknown is scary for doctors, they avoid anything and everything that isn't in their handbooks - for good reason! People sue people on a whim.