It’s the calories not the sweeteners. The increase in caloric consumption as noted in Maureen’s comment is right on. Don’t listen to the “natural” recommendations. I’ve had some success with using Stevia, but the taste is not as crisp for me.
My husband works at a grocery store. He says you wouldn’t believe the people that buy a load of junk food like cookies donuts and candy bars and then they get diet soda to go with it. Something here is causing weight gain.
I have been working with a certified diabetes educator who is also a registered dietician and has a background in biochemistry, and who is a Type 1 diabetic herself. The way she explained it to me was like this: when you ingest something with artificial sweetener, your brain receives the message that you are ingesting a large amount of sugary calories, so it primes your body to receive those calories, and if you don’t receive those calories, you will have cravings and be more hungry than you should be. I was drinking large amounts of diet soda every day and have gone to none and I can honestly say my hunger pangs have gone way done, so I’m doing less impulsive eating, and I have lost five pounds.