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

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?

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?

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

No, he drove a Honda, he just didn't talk about it, it's in the Bible, John 12:49