This may explain my observation that people who drink diet sodas drink a LOT of diet sodas, while people that just drink soda do so occasionally.
Given the choice between a diet soda and water? I'll take the soda, thanks, unless I'm really thirsty. Better taste, without excess calories.
Maintaining a healthy diet isn't rocket science; drinking diet soda rather than water won't influence your weight unless you alter your diet in other ways.
That's what self-control is for. Rats don't have much of that.
Neither do humans. That's why rats are such good test subjects.
The point of the study is that your brain gets the pleasure, but no caloric intake to go along with it, so you feel more motivated to get more calories than you would have otherwise.