How much of the obesity epidemic can we attribute to personal decision-making?

[AggregateDemand]

It is related to industry. During prior generations, whole foods were cheap and processed foods were prohibitively expensive. Sugar was expensive, and the US imposed tariffs and anti-trade barriers on sugar so the industry switched to high fructose corn syrup in the late 1970s. Sweetener prices tumbled, and obesity rates started to climb. Now, sugar processing has been refined, and sugar prices are plummeting, as well.

However, cheap plentiful calories are a blessing, not a curse, and we should place an expectation on people to exercise their freedom responsibly. In very limited instances, it may be practical to subsidize whole foods to make sure that people actually do have access to food choices, but those programs should be limited in scope and focused on the most desperate communities.

[AggregateDemand]

I don't get why America is so different?  In Britain they have McDonald's and in many countries that's the cheapest food I can find.  But most other countries don't seem to be having these problems.

The UK does have a problem with obesity. If you speak English as your first language, you have a much higher chance of being obese.