Currently on a diet. I have no idea how this weird question even got into my mind, but here we go.
In: Biology
There was a study where a man who was morbidly obese stopped eating altogether and only took vitamins and amino acids and drank water and he had no lasting side effects if I recall correctly.
The biggest problem would be malnutrition. Their body would keep itself fuelled by burning the fat, only after which would starvation itself be a concern. However, they would be severely deficient in just about every form of nutrient we require – vitamins, iron etc. This would leave them at severe risk of many health problems.
its called waterfasting, the current record is for a guy around one year i think, or maybe 400 ish days, generally depends, u need vitamins to stay for longer since vitamins and minerals dont get stored, the first 3 or 4 days are the hardest, if u pull through them the rest is ez and u get a surge of energy and clarity, u lose a lil bit of muscle but not as much as u would think so its worth it
He would survive much longer than an average person as his body will have a huge supply of fat to use as calories. His muscles and organs, etc. would begin to deteriorate as the energy reserves stored in fat is not sufficient to maintain these. Poteins are needed for repairs as these are used. There are also other nutrients required for various functions, especially the brain.
You need the vitamins and minerals that get lost through metabolism and urine. Additionally amino acids cannot be fully recycled so you would need to add those as well, or the body will take apart muscle including the heart muscle to obtain those amino acids (protein = multiple amino acids).
If those 3 points are met, then yes the obese person would only starve once their fat storage runs out. Depending on degree of obesity, this will take over a year.
Without those vitamins, you will develop conditions like scurvy within a couple of months (hair falls out, wounds don’t heal, old scars break open) as well as other vitamin deficiency disorders.
If you do not provide sufficient quantities of minerals, including regular table salt but many others, it will only take weeks at max before you die from most likely heart arrhythmia, because those minerals like sodium and potassium are required for all nerve signaling and with too low (or too high) levels the heart stops working.
So supply the vitamins, minerals and minimum amount of protein/amino acids in the drink, then the person would indeed survive for as long as their fat storages last.
Since fat has 9kcal per gram, or slightly less in actual body fat, that’s around 3500 kcal per pound of fat.
So with a fully sedentary lifestyle, you could use about 1 to 1.5 pounds of body far per day.
If you are 100 pounds overweight you would go 70-100 days before your body weight reaches ‘normal’ levels, and another 30-60 daya before your body has no more accessible body fat and starts using proteins from muscle etc to turn it into glucose for energy, at which point even with now sufficient food there’s a high risk of death.
Someone who weighs 600 pounds, could go about one and a half years easily, assuming as always, micronutrients and minimum quantity of amino acids are provided.
If you just dumped an average weight person and an obese person on a deserted island with only fresh water to drink, their life expectancies (on average) would not be drastically different, as the lack of minerals and water soluble vitamins would occur nearly independent of body fat.
If you had some minor sources of food, the obese person would potentially be able to last longer (depending on the amount of minerals and vitamins they are able to find)
There are two kinds of things we get from our food, broadly called “macronutrients” and “micronutrients”. The first of these is just energy, and this is something the body can use stored fat to produce. The second of these are things the body does not need a lot of, but can not produce for itself, and must get it from food. If a very fat person only drinks water, they will not get any micronutrients and will develop some sort of disease. A well known example is scurvy, from not having enough vitamin C, but there are others related to a lack of other micronutrients.
If a person gets all the micronutrients they need, for example by getting them from pills, and drinks enough water, they can essentially survive indefinitely for as long as they have enough fat to burn.
Actually doing this requires careful medical supervision to make sure the micronutrients the person is getting are sufficient, because obvious signs of not getting enough may no show up until it becomes a serious problem. Also ending the fast and resuming eating normal food again after a long period of not eating can itself cause medical problems, so that process needs to be handled carefully.
As others have mentioned, a man called Angus Barbieri did exactly this. It’s probably not a good idea, though.
A group of [IRA fighters imprisoned](https://en.wikipedia.org/wiki/Bobby_Sands) by British forces went on a hunger strike and died, it was found that they died when their body fat reached zero.
The winner of the first Survivor in the US was over weight at the start and dropped a huge amount of weight (as did everyone else). By the end he was the only one thinking clearly and his extra weight was considered helpful. Afterwards he went to jail for tax evasion so he wasn’t thinking that clearly lol
Yes and no.
Fat is, to put it simply, food-energy your body sets aside for later. It contains a few *essential* vitamins, but not everything you need. The fat we evolved to store is, basically, an emergency energy supply. It has enough oomph to keep you alive during periods of low food (read: winter), but it isn’t meant to be your only source of energy.
You eventually will die of malnutrition related illnesses, as your fat doesn’t store proteins, amino acids, and the slew od vitamins and minerals you need to survive. You won’t get any iron and will grow anemic, the lack of vitamin C would lead to scurvy, etc.
But you *could* take some vitamins and be okay. If you took, say, a multi-vitamin, plus some other select supplements, you could survive off only fat.
1 pound of fat is about 3500 calories. So you could lose that in a day.
Beware of salt loss, and constipation.
I did twenty days once
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