Calories in - calories out fails to explain why people consume and expend as many calories as they do. As the series discusses, many calorie sinks such as fidge

Calories in - calories out fails to explain why people consume and expend as many calories as they do. As the series discusses, many calorie sinks such as fidgeting and body temperature are subconscious or autonomic and seem to be used by our bodies to help regulate our weight. And some people clearly have very strong hunger drives. Clearly something has changed over the past hundred years. Saying that we got richer fails to explain why the rich people of yore, while fat by the standards of their day, are not fat by modern standards. Saying we have gone down hill in terms of sticktoitiveness is not really a verifiable claim and does nothing to offer a solution. So it is absolutely worth further investigating what is going on.