I'm watching a serie about E-numbers and in the third episode they are talking about sweeteners. They did a test were a sports team got divided into two groups and one of the groups got to drink normal soda with sugar and the other group soda with sweeteners.
They then let them eat as much food as they wanted and found out that the group that got the soda with sweeteners ate in average 140 kcal more than the other group. They also say that they have done other studies before and have seen that people that consume artificial sweeteners consume more calories.
You can see that experience in the third episode after about 40 minutes in.
They are all in english! Watch them all here: