Obesity rates have come about because eating and exercise habits have outstripped genetics. Let me explain.
For thousands of years, people went through times when crops and livestock were plentiful, and you could eat hearty (we call this feast times), and everyone put on a few pounds. Then you would have another time, when crops were poor and livestock were even worse,, we call this a time of famine. Genetics were designed for the feast/famine cycle so when times were good, the excess could be stored in the body, so that when the time of famine came, you had enough to keep you alive, with what little you could get. With the wonders of modern shipping, we have eliminated the famine part in North America The last famine in North America was in the 1930's. Which is why so many people get fat, genetics makes the high fat, high sugar foods, what we prefer, to make the store as large as possible, for when the next famine cycle comes along.
The only way to fix this, is for the individual to VOLUNTARILY induce an artificial famine cycle, by intentionally eating less then they need to survive, while at the same time, making sure they burn as much as possible. Trying to convince someone to do this, that does not want to, is an exercise it futility. Convincing them, that they want to is the key....