Artificial sweeteners still trigger an insulin response, just like sugar. In the absence of glucose to leech out of the blood stream that then makes you hungry.
Studies aren't really 100% conclusive yet probably largely because individual differences are high, e.g. if you drink yours with a meal that has a different result than when drinking it without one and then having an extra snack. For the whole population diet sodas might just be a tad worse for weight gain than regular sodas, what we know for certain is that they're not significantly better.
But I’ve lost 100 pounds in the past two years and I’d really like to stay this way.
0.5 to 1% of body mass per week, no more, or you're likely to bounce back because ancient circuits in your body and brain think that they need to be ready for famine. In the end all those numbers don't really do much it's "eat healthy (meaning enough micronutrients), ideally varied (that's what seasons are for IMO), and only when you're hungry". Where hungry means your body needs energy, not your stomach isn't full, or you want to distract yourself, or whatever. We all do have perfectly sufficient weight regulation circuitry, no spreadsheet needed, and if you hear someone tell you "it's all about willpower" then what they have is an intact, unobstructed, circuitry which means that they don't need willpower.
And yes profit-driven food design is notorious for kicking that circuitry out of whack, our social environment does the rest: Merely eating only consciously, bite for bite, can reset the whole thing but who nowadays has time and nerve for that -- which is why you often see it done by proxy, studies show that pretty much any type of diet restriction leads to more conscious eating and therefore better weight regulation, restriction as in what you will eat or when (e.g. only seasonal stuff), not calories. Some set of rules restricting what's available for you in particular (that is, e.g. not eating pork when noone in your country even sells it doesn't count). The reason vegans and vegetarians aren't as prone to obesity has preciously little to do with what they eat, but that on average they spend more time thinking about what they eat than the rest of the population (modulo vegan malnourishment different topic but if you're a vegan you need to know your shit, it's not optional).
