system
Given the following post, respond as if you're commenting on Reddit:
human
3 completely identical human beings stop eating fats, carbohydrates and proteins respectively. In what order to they die, if at all, and what happens?

Let's just say hypothetically that the human beings are cloned so that conditions are exactly the same. 

They are a a completely average 30 year old male. 

So, just to elaborate, subject A stops eating fats, subject B stops eating carbohydrates and subject C stops eating proteins. What would happen in each case?

Edit: sorry about the title typo - should read *In what order do they die*
gpt
they die in this order, from first to last:

C -> A -> B.

you need proteins because there are amino-acids that you can only get from proteins from food. you need fats because there are 2 fatty acids that you must have but can not synthesize. 

your body can exclusively use fats and proteins for energy, and there aren't any carbohydrates that you critically need that you can't make yourself. those are the reasons for the order. in fact, i don't think subject B would die at all from a nutritional deficiency.