I think sugar is additive, like tobacco, and with lots of bad health outcomes and because it is additive that is why it is hard to cut it out. Watch the movie Sugar Coated for one take on this line of reasoning.

It likely is as easy as cutting sugar out, just like smokers should cut cigarettes out, it is just hard to do because of the additives qualities of the drugs.

And like cigarettes, cutting down isn't really as effective as cutting it out nearly entirely, because a little bit of an additive drugs primes you for more.

That 36% of US adults are considered obese does not make it obvious that losing weight is any more complicated than cutting sugar & carbs.

First, "common sense" dietary advise is that fats are bad. That's why you see foods marketed as low-fat. Because common sense dietary advice has been focused on the wrong thing (fat instead of sugar/carbs), most people's conception of "eating healthy" is wrong.

Second, the route to being financially healthy and stable is incredibly simple: spend significantly less that you make. Yet some how a huge percentage of people in the US spend beyond their means. Could it not also be the case with cutting sugar & carbs that even if people actually knew what they needed to do, they still would not do it?