Which will you drink more of? And if you're having these drinks with lunch or dinner, how would each drink affect the amount of food you eat?
The answer -- from the Universite de Bourgogne et Institut Europeen des Sciences du GouEt et des Comportements Alimentaires in Dijon, France, -- is that you'll drink more of the sweet drinks (diet or regular) and the least of the orange-flavored seltzer.
As the journal Appetite reports, the amount you drink doesn't influence the amount you eat. So if you were counting on filling up on fluids to reduce your appetite, forget it. And if you thought that having all that sugar would make you feel full, forget that too. All regular soda does is increase your calorie intake.