You are not a population.
As I said, yes, individuals can make changes that improve their likelihood of losing weight. There’s no dispute about that. At the same time, that’s not the same as finding a way to resolve the problem of obesity on a grand scale.
Think of it this way: remember when I said obesity isn’t caused by eating too much in the same way that being poor isn’t caused by not earning enough? Yes, you can give an individual advice about how to escape poverty. The equivalent of telling people “Just eat less”, say “Just go out and work harder, earn more”. To go further, you can recommend social programs, you can encourage education, you can train job skills, you can help them learn how to write a resume. That isn’t the same as solving poverty on a grand scale, and it doesn’t mean our work is done.
The average American is flatly overweight. Clearly, there is a problem. Yet, just knowing about nutrition and good choices clearly isn’t enough. What makes one person an alcoholic and another not? What makes one person stop when they get five pounds overweight and another not stop at fifty? Yes, bad choices are made by people everywhere, but clearly that’s not the only issue; otherwise why would some cultures (e.g. America) and some populations (e.g. the poor) and further some individuals tend toward obesity?
I think there are lots of reasons why people are overweight. There’s no one-size-fits-all (snerk) solution. For one person, the answer may be “stop sucking down Frappuchinos”, but it really doesn’t come close to resolving the physical, cultural and psychological reasons why some people just have a very hard time losing weight and keeping it off with currently available methods.
It really wasn’t all that long ago that we considered things like sex before marriage and masturbating as moral failings. These are behaviors and yes, the person does have control. Yet, most people find it funny that people suggest that abstinence should be the only available birth control. I’d suggest that it’s just as silly to tell a population of people that it’s easy to go without sex or masturbating as it is to tell a population of people that everyone can be thin through willpower dieting alone. The need for sex is a compulsion, the need for food is a compulsion, and for some people those compulsions seem to be somehow broken.