Would be nice if it works out like that.
Sadly, a lot of the issue with obesity in the US is straight up dietary. (of course, viral vectors that upregulate fat storage do not help matters) The rise of obesity correlates nicely with the "Heart healthy! Lower fat! Lower salt!" change in formulations of basically everything on the market. When you have food that lacks those, you have food that is bland and unpalatable; But the food industry learned that if you load it with enough sugars, people will still buy it with gusto. Fast forward a few decades, throw in some lobbyist action from Iowa Corn Growers Assn, and the southern states sugar lobby, and you have grossly inexpensive HFCS, and captive expensive sugar (which helps keep HFCS prices low), which are less expensive than the original fats that were added for flavor and texture. (any fats for texture now tend to be highly processed waste seed oils, like cotton seed, that have been hydrogenated into something just short of being something more like a paraffin wax, than what it was intended to replace, metabolically speaking). Am I suggesting that the original formulations are somehow healthy? No. No I am not. Just that the newer formulations are even LESS healthy.)
If you are seriously interested in combating the heart disease and obesity epidemics, you are gonna have to buckle down, and outlaw highly processed foods, in their entirety. (Diabetic fat women who "Just cant live without their DingDongs!", would just have to learn how to make their own snack cakes at home.)
Given that this would mean crippling a huge chunk of the market for not just the snacks themselves, but all the products used to make them (like the afore-mentioned waste seed oils, and the processing to hydrogenate them), and it could have serious economic backlash from being done. At least people would be significantly less likely to die from heart attacks, type II diabetes, and CHF (due to obesity), but no politician that is not suicidal is going to go down that road.