First: the lipostat mechanism needs fixing, because evolution built what worked, not what would be ideal. Exposure to overeating should not result in a life sentence of obesity.

Second: replace capitalism. There is a reason why there are food deserts, why people have to make the choice of nutrition versus quantity, why people aren't educated on nutrition, why people don't have the time or emotional energy to work at food after they've done working at work, and it's capitalism. Or more precisely, any money-and-work economy. Capitalism just makes it run wildly out of control.