My view, being in the middle of it, and as someone who has probably cut total calorie intake 50% or so: it is definitely extreme, but it never feels like pure starvation. Sure, you want to eat food, and the time between the afternoon shake and the HSM can be kinda brutal, but you’re constantly “fed”.
Naturally, it’s fewer calories and probably fewer carbs than a lot of us are used to, so it’s not that fun, especially in the earlier days, but I don’t feel like it’s actually all that extreme in terms of how each day passes. Sure, I wanted to eat Shake Shack and pizza this weekend when my kids were having it, and I would love to have a little bit more food during my HSM, but as Chris says, i do think that’s sort of the point. I definitely have some hangry moments, especially before dinner, but also just part of the deal.
One other thought: it works pretty fast. Thus, you get some positive reinforcement quickly, which is amazing and super motivating for me. Use that momentum to push you through the tough times.
I have no idea what type of diet is best for certain people, but I was attracted to this for 1) the prescriptiveness and 2) the customized strength component that separated it from a lot of other diets for me. Literally zero thinking involved, other than planning out each individual day, but still get to lose fat and maintain / build some muscle.