Not everyone can eat a pound of candy loose weight, with one caveat. If you starve the people to the point where it doesn't matter if they have no energy, and it's well below anything the body can compensate for by adjusting metabolism, then that works for everyone; but only in that extreme circumstance.
People also make the assumption that we know the cause/effect relationship with this. We don't. There is no evidence.
Eating a lot of sugar is kind of like smoking. It may cause severe health problems in a relatively short period of time, or you may die at 105 without a hint of a problem.
You also can't confuse the amount of food with the healthiness of it.
Grains of course aren't anywhere near as bad as sugar, but it does look like they cause some inflammation. That can be bad in higher quantities, but in smaller quantities it would have very little affect. If grains were less refined as they used to be, they would contain so much fiber you simply couldn't eat too much of it. It's kind of like fruit that way, where you simply can't eat enough of it for the sugar to be a problem. Not to mention you also have a couple very healthy options for starchy carbs when you need that. Yams and brown rice are pretty healthy, and I think turnips are too. If grains weren't being represented as this super-healthy thing that should be the bulk of your diet, they probably wouldn't be a problem. It's just that a large percentage of the recommended diet is that.
People probably feel better not eating as much grain and mistakenly think they are gluten intolerant, but it's just a faulty assumption as only a very small percentage of the population are.
People don't reach their goals because they're lazy and lack the willpower to get there - it's that simple.
Now this I think is just silly. It's a blanket statement, absolutist for one thing, but it's also demonstrably false. It's not very controversial that genetics is the biggest factor in bodybuilding. There is also the very different genes that are active in different people predisposing them to having this problem or that problem. Not every natural bodybuilder looks like Steve Reeves, and not every steroid user can compete in the Olympia contest. Hard work will only get you so far.
Now I certainly won't dispute that most overweight people I encounter don't have a willpower problem, because they most certainly do. I can tell someone how to lose weight, get them losing weight, but they can't stick to it. They know I'm right, they've tried it and seen that it works just like I said. They still can't do it. I'm just saying that isn't the case for everyone.