It's not about the carbs, it's about total calories. It has been that way since the beginning of time. Those guys get fat because they consume more energy than they burn, just like everyone else.
The point of Michael Phelps and the amount of food he consumed was to point out that it doesn't matter how much you eat as long as you burn it. Just like the guys who ate McDonald's for several months but lost weight due to increased exercise.
The people with the longest life expectancy on earth are also the ones with the highest per-capita consumption of carbohydrates on earth. Go figure.
This is a debunked study based on cherry picked data. This is not true. The people with the longest life expectancies actually eat high fat/low carb ratio diets.
Its also about metabolism and what you eat does impact your metabolism. Not all calories are the same.
http://chartsbin.com/view/1154
So you are saying (from 2009 numbers) Bangladesh, Burundi, Democratic Republic of the Congoat all above 80% calories from carbohydrates live longer than Israel, Italy, Spain, the US, Netherlands, Switzerland, and Samoa (which are all under 50% calories from carbohydrates)?
You are so wrong, I am surprised you know how to breathe!