Just adding to your points: > The human body is very efficient. I'd be extremely surprised if my 15 minute bicycle commute to work burned more than 100 calorie

Just adding to your points: > The human body is very efficient. I'd be extremely surprised if my 15 minute bicycle commute to work burned more than 100 calories on top of my BMR. There's just no comparison. Also, biking is exercise, and we should all be getting some exercise daily. If bike commuting replaces some time you'd spend at the gym, the question of how much energy exercise consumes is irrelevant since you'll be using that energy either way. As others have mentioned, that can also save you the time of going to the gym in addition to the other benefits. > I'd link to icebike.org where they used to have pictures of people cycling in Chicago in winter and articles on suitable clothing and tires, but that domain got bought out and commercialized into some mountain bike advertising site. I live in Wisconsin and bike all winter. Some combination of fat tires, studded tires, and internal hub makes it easier. With my studded tires ice is basically a non-issue. It's also easier to stay warm than you might expect. If you have any kind of jacket on your core can get hot really quickly while cycling. You do need decent clothing to protect your extremities.