Can Sugar Substitutes Make You Fat? - TIME
Looks like your body isn't as easily fooled as you might hope for dieting, apparently the body expects calories to go with sweet foods, and when they don't it tries to make up for it. So when you eat food with artificial sweeteners you may end up eating more food as your body tries to acquire the calories it expects to go with the sweet taste.
The experiments described in the article were carried out on animals but the results fit data from other experiments on humans, suggesting it's likely that the animal results apply to humans as well.