Then why do type 1 diabetics only count carbs? A diabetic can eat as much protein, fat and fiber as they want, but have to match insulin levels to their carbohydrate consumption (except fiber).

I'm highly simplifying, but carbohydrates are converted to blood sugar which insulin converts to energy at a cellular level. Insulin is needed so your cells can feed off the blood sugar. The blood sugar that isn't used is stored as fat. Carbs are quickly and easily converted to fat. Other forms of food can eventually get converted to blood sugar, but not as easily and quickly as carbs. You absorb protein, minerals, vitamins, fibers, etc. very differently than pure Carbs. So a Carb rich diet will make you fat. Diabetics are only concerned with Carbs because they have the highest impact on their blood sugar level.

Further, America has proved this. Few cultures consume as much carbohydrate rich food as America, and as a result, they have the biggest issue with diabetes, obesity, etc. Carbohydrates are the cheapest food to buy (fast food and junk food are very heavy in carbohydrates), so a disproportionate number of low income people have obesity problems

Dude, its the carbs.