I've had better luck with low-carb vs. low-fat diets and here is my explanation: certain foods cause overeating--high-ft/high-sugar combos. Both fat and carb (sugar) influence weight gain but when taken together they are dangerous because, like alcohol to an alcoholic, they begin an overeating cycle (overeating on everything, not just the initial problem food). But if you restrict carbs you tend to cut out bread, pastries, cereals, ice cream. If you restrict fats, you tend to cut down on butter, oils, fatty meat. It is a lot easier to overeat on bread and cereals, for most of us, than butter and bacon. Perhaps that just comes down to what some people might term the addictive component of sugar or the satiating element of fats. I call this the Donut Pizza Theory of Everything.