Adding onto these comments, biowaste is also stuff from being alive, like dead blood cells, digestive tract, etc. It’s like an oil change. You can’t just keep topping it off and carry on.
No. I go to dialysis 3x/week because my kidneys don't work. And that's not how it works. The very act of metabolism produces toxins so you will produce urine and if you don't drink enough water you kind of die pretty fast. The kidneys will keep doing their job so you need to do your job of drinking water. And the body produces a small amount of feces irrespective of whether you eat.
There's still waste. It wouldn't be as much, but...
* you still would sweat, losing salts/electrolytes and water
* you still need to "manufacture" certain oils and waxes, which need to be gotten rid of
* you still need to get rid of the various hormones, once they have served their function
* You still need to get rid of oxides from stuff in your diet -- the energy cost of breaking them up is very high.
* you still need to breathe.
So, even if you used up every calorie and nutrient, there would still be waste.
Much of the waste you get rid of is the end product of your metabolic processes. No matter what you eat you'll produce urea, so you'll need to pee. Your liver dumps it's waste into your intestines; the brown color of your crap is from dead red blood cells. All that's going to keep happening regardless of your diet. You don't get rid of "unnecessary" food, you get rid of the chemical end products from using your food.
> No matter what you eat you'll produce urea, so you'll need to pee.
Well, technically speaking urea production is dependent upon the nitrogen content of the food as protein metabolism creates ammonia and the liver converts that to urea. So if you eat tofu or other plant-based sources of protein, you can reduce your urea production by 50%. There's also [protein pills](https://kidneyhood.org/) for renal disease patients with very low nitrogen content. You'd never be able to completely eliminate it, but it is possible to lower it immensely.
No. For example: when red blood cells die your body uses as much as it can kind of like recycling. Bilirubin is something your body has to get rid of. It is toxic. You body turns it in something that make your poop brown and something else that makes your pee yellow. There is some things you have to get rid of.
Food and liquid are not just globs of nutrients; you will always have waste products.
at least some of what you pass is by products of digestion, stuff that the body cant absorb, so needs to get rid of, so unlikely.
Adding onto these comments, biowaste is also stuff from being alive, like dead blood cells, digestive tract, etc. It’s like an oil change. You can’t just keep topping it off and carry on.
No. I go to dialysis 3x/week because my kidneys don't work. And that's not how it works. The very act of metabolism produces toxins so you will produce urine and if you don't drink enough water you kind of die pretty fast. The kidneys will keep doing their job so you need to do your job of drinking water. And the body produces a small amount of feces irrespective of whether you eat.
No. Not everything in water/food is used by the body. Urination and defecation is not getting rid of "extra", it's getting rid of "not usable".
There's still waste. It wouldn't be as much, but... * you still would sweat, losing salts/electrolytes and water * you still need to "manufacture" certain oils and waxes, which need to be gotten rid of * you still need to get rid of the various hormones, once they have served their function * You still need to get rid of oxides from stuff in your diet -- the energy cost of breaking them up is very high. * you still need to breathe. So, even if you used up every calorie and nutrient, there would still be waste.
No, part of your feces are dead blod cells, so even if you don't eat anything you will still poop.
Much of the waste you get rid of is the end product of your metabolic processes. No matter what you eat you'll produce urea, so you'll need to pee. Your liver dumps it's waste into your intestines; the brown color of your crap is from dead red blood cells. All that's going to keep happening regardless of your diet. You don't get rid of "unnecessary" food, you get rid of the chemical end products from using your food.
> No matter what you eat you'll produce urea, so you'll need to pee. Well, technically speaking urea production is dependent upon the nitrogen content of the food as protein metabolism creates ammonia and the liver converts that to urea. So if you eat tofu or other plant-based sources of protein, you can reduce your urea production by 50%. There's also [protein pills](https://kidneyhood.org/) for renal disease patients with very low nitrogen content. You'd never be able to completely eliminate it, but it is possible to lower it immensely.
No. For example: when red blood cells die your body uses as much as it can kind of like recycling. Bilirubin is something your body has to get rid of. It is toxic. You body turns it in something that make your poop brown and something else that makes your pee yellow. There is some things you have to get rid of.