Is that available in pill form?
Seriously though, there is no reason for people to be overweight nowadays. Lay off the frikken carbs and start walking (and move on up to running, biking, or rowing, etc., as soon as you're ready).
That's all well and good. Everybody knows all that stuff already and it's not working for the 40% of the country that is obese. Also if you think it's just the U.S. then you haven't been to Europe lately, the U.K. and Germany are danged near as fat as we are. For whatever reason, people aren't able to get the weight off and the obesity is causing all kinds of health problems. You can wag your finger at them and snarl about how they're fat asses or we can apply modern medicine to fix some of the problem which in turn will make their lives better while reducing the enormous associative medical costs of obesity that we spend every year. The only downside is the sanctimonious won't have as many people to look down their noses at.
Some people have health issues that prohibit walking, cycling, etc. I lost a decent amount of weight doing no/low carb, without exercise. Am slowly adding a little more carbs and probably am gaining some weight, but not much.