"Fats make you fat" is a flat-out lie.

The effects of carbs - especially carbs with plenty of refined sugar - are the developed world's number one health care expense. They don't just cause obesity and diabetes, they also create inflammation which leads to heart conditions, strokes, and other life-changing disorders.

Unfortunately the food labelling industry has been promoting falsehoods for most of its existence. Labelling carbs more clearly, licensing sodas and diet sodas to limit access, and starting health programs to educate the population about carb abuse would do more to improve public health than anything else.