Often when I explain that we have the highest healthcare costs of all industrialized nations and the lowest life expectancy, the opposition mentions that it could easily be explained by how obese we are. That to me is similar to how global warming deniers like to mention solar this or ice age that which could be the real explanation. Usually this ends the conversation.

Reply with, "yes, it could be a factor, but its explanatory power turns out to be much weaker than you make it out to be."

26% of Americans are obese, whereas 22% of Britons are obese. In 2005, the US spent 15.2% of its GDP on healthcare, while as the UK spent 8.2%.

So we're 18% more obese, but have spent 85% more on healthcare. The obesity argument doesn't have enough explanatory power to be the main reason American healthcare is so expensive.

Meanwhile, 22-31% of the American healthcare costs are in administrative, marketing, and profits. Single-payer systems (including Medicare) only spend 3%. If you cut out the costs associated with the capitalist friction, you bring our healthcare costs to 11.1% to 12.3% of our GDP, which brings us more than half as close to how much the average non-US industrialized nation spends (9.1%).