It does take a lot of exercise to impact weight significantly, but it should be encouraged as much as possible by setting up more parks, safer running and cycling trails, more dirt trails, more outdoor exercise equipment in parks and so on (there's been a rise in such equipment in recent years), and less car culture and the physical infrastructure it involves. It can be very dangerous to just go for a run or especially a bike ride in today's busy streets. In Europe, they have dedicated bike lanes in big and small cities that are separated from the road traffic. They also need to encourage more exercise in schools. Kids today are unbelievably obese. In terms of food, they need to stop subsidizing a lot of corn and wheat production that ultimately go to high fructose corn syrup and non-whole grain carbs. Subsidize fruits and vegetables, as well as legumes and nuts. Tax sodas and chips and limit portion sizes. We have to be helped because our brains want the sodium and sugar and carbs and society can't afford 40% obesity rates. It's all much worse in the Trump states but it's a national problem in the sense that just about every state has over 20% obesity rates, as compared to a lot of other countries with rates closer to 10% or below, and same for BMI.