24 years of age...My body fat is at approximately 10% with exercising 4-5 days a week and more of my weight is in muscle than it is in fat...I consume a lot of carbs, approximately 200-300 daily. But these are good carbs from whole grain/high fiber sources, which is why they are not tacking weight on me.
When I was 24, I couldn't gain weight despite working at a fast food restaurant and eating all I wanted of that crap, and then living on large pizzas the rest of the time! Youth overcomes all sorts of bad diets, as long as the person is somewhat active and has a decent metabolism. Wait until you hit 30. ;-)
Your last statement is simply not true with regard to why obesity has sprung forth in america. It is a combination of consuming a lot of processed foods and meat induced with hormones and high fat.
Processed food, yes. Meats, nope. There's just no proof of this. I've been paying close attention to this topic for 8+ years, and I've yet to see anything that shows eating meat leads to illness or fat gain. Note that no one just eats meat. For example, don't blame the burger patty, blame to bun. Subway sandwiches are a complete disaster because they're all bread (and the overly processed meat barely rises above pet food standards). The only way to lose weight eating Subway is to control calories.
Wholehealthsource opines that it may not matter all that much what proportion of protein, carb and fat we eat. Maybe the massive differences of opinion stem from the fact that it's possible to be healthy on a variety of diets??
As explained in that post, the Kitavans are active, and they only eat quality carbs, no grains. You can definitely get by on a higher carb diet if you're active and the carbs are quality, wholesome, and varied. But, while humans can live a full, healthy life without carbs, the same cannot be said for protein or fat.