Not to put you down bro but you are very wrong. People can vary different metabolically. For example, even though it is very rare I have delt with two people who had thyroid issues. As most people may or may not realize is it's not just a matter of consuming less calories over a period of time. If it were that easy no one would fail on a diet. I have had literally dozens of people come to me who's progress has come to a halt after weeks of dieting no matter how low they go on their calories.
This is very true.
I've been loosely monitoring my friend's diet and he's tried every approach over the last year. He's done keto, changed his cardio, we've worked on his macro timing, etc... he's lost a ton of weight but still has quite a fair amount of adipose. He has a messed up thyroid and low test. I've urged him to go back to the doc and maybe he'll be seeing an endo soon.
The body is full of very complex systems that are still misunderstood. Bodybuilders have pioneered eccentric ways to solve these challenges though. You just need to isolate and identify what's wrong and try different approaches. A lot of it is hit and miss, or just intermittent. Genetics can be a bitch. I don't claim to be a personal trainer or dietitian or anything, but I've helped out friends and family and everyone is very different. In the beginning, you can simply truncate one's caloric intake, but after they lose water weight and easy pounds it gets MUCH more difficult.
I don't know what Adam's been advocating lately, but for the most part I eat relatively clean... but I give myself some leniency. For carbing up this evening, I just ate a few "Two Bite Brownies" with walnuts lol.... I could have had a low glycemic carbohydrate but I needed a quick fix and ate good enough all day to justify it. Why sit down to a bowl of plain oatmeal, popping K-R-ALA and PLCAR and topping it off with some cinnamon and tuna. Bleh... unless someone's competing or really hitting a plateau, I don't think they need to be too stringent. But then again, I'm not a fatass who needs to lose 40lbs to see an ounce of muscle poke through.