That's a wrong argument. Sugar is three times less calorie dense than fat. (that's not an argument for sugar or against fat, just a fact).

Not a study but a theory:

Sugar causes a blood sugar roller coaster with an energy crash at 2-3 hours that appears to be specifically designed to get us to over eat. In nature sugar exists in large quantities only during the short period of fruit being in season, and thus it makes sense there would be a mechanism to get us to over eat during the limited window of fruit availability.

Sugar triggers our “eat it before it rots” mechanism.