> It sounds like your conclusion is roughly that, sufficient nutrients aside, it doesn’t make a damn bit of difference which columns the calories are under, not just in terms of weight management, but general health.

My conclusion is that but slightly more conservative: more that science is really hard, and we have not been able to show that macro nutrient composition matters nearly as much as we thought. It may still matter quite a bit, though you'd expect it to be easier to measure if it did, but again science is hard.

> Yet, I struggle to entertain the possibility that the guy eating a lot of pizza and ice cream and candy is going to encounter health problems a lot sooner than someone of the same CICO eating avocados and chicken and broccoli.

I can show you small scale examples of people doing this and not having problems (http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/...) but I can't show you a strong epidemiological study that confirms this, unfortunately.

> What about skinny people who get heart attacks?

This does happen, though of course far more rarely. Lots of stuff impacts this (genetics etc.), and I don't know nearly enough about heart attacks to comment, but I will say broadly that one of the worst things you can do for your heart, and most of the rest of your body, is to be fat, and the only way to be fat is to eat excess calories.