Diet sodas and gaining weight

I am sure you have heard all about how diet sodas can make you gain weight, but did you really find out how they came to that fact? They did a study on rats and found that the rats that were given saccarine in yogurt were more likey to eat more than the rat given just regular yogurt. For one thing we are not rats and we can choose if we want to eat more or not. The study did not find that the diet sugar made the rat gain weight by itself but by encourging the rat to eat more. Of course the food was available to the rat as well. Cooped up in a cage with nothing else to do I guess they did not take into account the boredom factor of eating.