That is fact yes. If you take in more energy then you burn you will gain weight. About the overeating, that is the hard part for most. It is almost as if it is genetically programmed in us to over eat. Remember not long ago our species(and ancestors) was always in a struggle for food and always had to binge due to not having a steady nutrition source. This new world that has plenty of food is a relatively new concept and obviously it shows, as so many are overweight.