I've dieted and lived with and without artificial sweeteners and have experimented with allowing none, one, two, or all. Personally I've seen no difference in either weight loss or symptom issues with any of them. I've also researched the opinions and research both pro and con (and researched the credentials of the reasearchers).
I have decreased my diet soda consumption, but as much for financial reasons as anything else. The changes I've made and why
1. I rarely drink "brown" sodas. They're considered more harmful, especially for teeth. I forget the actual ingedient.
2. I use a straw (reduces the damage to tooth enamel). A lot is made about the "caustic" nature of diet soda, but many foods are as damaging or more so. Oranges and other citrus fruits, for example, especially juice are even worse for teeth than soda (chewable vitamin see is VERY bad). If I were to drink orange juice I would also use a straw. After I eat an orange, I rinse my mouth.
3. I dilute artificially sweetened beverages. I started with Crystal Light type mixes and used just a little more water each time. I now often use twice as much water and throw in a flavored tea overnight. Then I fill a large glass and add a few ounces of diet Sprite or diet Mountain Dew (or their store brand equivalents). A whole can can last me all day (rather than the 6 cans I was drinkig ten years ago).
4. I combine sweeteners whenever possible. Most sweeteners have a synergistic relationship with other sweeteners, meaning that in terms of sweetening power 1 + 1 often equals 3 and 1 + 1 +1 can equal 5. This means that if you combine sweeteners you can use less of each.
5. I take a folic acid supplement. Aspartame can contribute to folate deficiency. If you eat plenty of fruits and vegetables this isn't a problem. I do eat plenty of freggies, but my neurologist prescribed the folic acid supplement for my fibro. That it is extra insurance against aspartame is a bonus.
6. I add TONS of ice to my beverage. I like the temperature and it dilutes the sweetener, but slowly so it's less noticeable than diluting with more water (especially if I already diluted it).
7. Something new I'm trying - alternating my diluted, iced, tea/Crystal Light/water/soda beverages with plain water, glass for glass.
8. Something I WANT to try - is carbonating my own water and other beverages with a soda stream.