The focus of the last hundred years (as far as diet was concerned) was about adding physical size and the easiest way to get that size was to eat lots of carbohydrates. The focus was not so much on the quality of the food, but the amount (as measured in calories or kilojoules). By eating more food, there is no doubt that humans grow bigger and taller, but we have also become much fatter. I tend to think today that the reason we are encouraged to consume the volumes of carbohydrates we do, is because it’s the only way to feed 6 billion people living on the planet. Foods like steak and fish are a lot more expensive than bowls of rice or potatoes.