There's apparently scientific studies that show how animals as well as humans tend to continue eating until they've satisfied a mostly fixed daily need for protein, mostly regardless of _what kind_ of food they're eating.

Now if people choose a diet low in protein/calories ratio, they'll have a tendency to ingest more calories than people who eat protein rich diets. Try eating eating 300 g of cheese/meat/tofu in one meal, it'll be difficult. Eating 300 g of chips/fries is something many people can absolutely do, if the chips aren't too salty.

One significant difference between our modern western lives and the lives of people tens to hundreds of years ago is IMO that people back then quite automatically used up all the carb calories of their comparably protein diluted diet because life required much more physical activity and came with less home heating than today. Today, most people will just not expend much of the caloric energy of carb rich diets and thus develop metabolic diseases and such.

A carb rich diet is usually fine as long as you expend the energy via physical activity.