Thanks for the answer. In the first reason to fast you are saying that people don't get omega 3 from corn fed steak. But when you fast you don't get that either? How is that a reason to fast then? I just feel like most people going into fasting because they have some health issue and try to fix it by doing fasting (I am not saying it does not work for them), I am trying to find someone who did not feel any problems and started fasting out of curiosity and see how it benefited them.
It's like having a bucket of water, when you eat it gets filled , then your body uses some of the water for energy. If you don't overeat the level of water in the bucket is always at the same, when you consistently overeat it overflows. When you fast - you can use the excess water you stored while overeating, it might be ok first couple years, but as since you are now eating less and your body uses water from a bucket more then you add to it - could it be that you will end up with an empty bucket at one point?
Your mental model of eating-as-a-bucket is broken, but you're not to be blamed since everyone thinks that and it's the official advice from most (all?) governments.
The calories-in-calories-out (CICO) model is true in a thermodynamics sense but it's like saying that Bill Gates got rich because he followed the money-in-money-out system. It doesn't really help us explain anything about Bill Gates. Or another, more damning, problem is this: We say a child gets taller because of hormones but they get fat because of calories. If you think about it for a while you'll figure out something is deeply wrong with the model.
This is a deep subject with a lot to say but I'd start with 'Why We Get Fat' by Gary Taubes. Then read his other books, then read Dr Fung.
But to answer you first point directly: What I'm saying is that people thinking they are eating healthy and actually eating healthy are two different things. Usually they think they are but aren't in reality, and fasting can help in a long list of ways detailed in Dr. Fungs book on fasting (and many other places too, his is just a good book). You can also find people on /r/fasting on reddit with a lot more detail.
It's like having a bucket of water, when you eat it gets filled , then your body uses some of the water for energy. If you don't overeat the level of water in the bucket is always at the same, when you consistently overeat it overflows. When you fast - you can use the excess water you stored while overeating, it might be ok first couple years, but as since you are now eating less and your body uses water from a bucket more then you add to it - could it be that you will end up with an empty bucket at one point?