Most of what I've seen has touched on two major points: cravings and how your body reacts to fake sugars.

I've seen that some bodies are fooled into thinking fake sugar is real sugar and it can impact how deeply into ketosis you are and I think I may have seen that it could potentially knock you out. (I don't have as good a working knowledge of the science of ketosis as many of our community members, but I do recall this. You're welcome to take it with a grain of salt until someone can give you better info than me!)

The most common advice about fake sugar is to avoid it because it triggers sugar cravings for many people, which can make you miserable or lead you to cheat.

Personally, I try to avoid it as much as possible because I am trying to eat more whole, real foods, rather than finding "work-arounds." But I also recognize that sometimes you need a little something sweet, and a diet coke is certainly better than something full of real sugar. I keep a couple diet sodas in the drawer of my fridge so its out of sight, out of mind, until I really feel like I need one (usually more of a caffeine thing than a sugar thing). I also have a tiny bottle of Torani sugar free syrup (made with splenda), which can be used in lots of recipes. I usually mix maybe a tablespoon with a pint of soda/seltzer water for a fizzy, slightly sweet drink. Again, I use this as infrequently as I can get away with.

A lot of people use the artificial sweeteners (liquid stevia seems to be the most popular for recipes) or consume foods made with them, but the one that is to be avoided at all costs is Malitol. Never ever ever have malitol!

I've had zero problems with Crystal Lite. I have diet soda and diet Rockstar energy drinks every day. I have seen no *credible* evidence that Aspartame/Sucralose/AcesulfameK hinder weight loss. They may have a minimal effect on insulin levels, but nothing near eating too much protein. Overall, they are still 0 calorie and so there is nothing there for your body to store as fat. In anything resembling a normal human consumption, artificial sweeteners do not cause any health problems whatsoever (like cancer or whatever).

If the drink you are having is caffeinated, that may very well affect your hunger and satiety. You probably will eat more if you're highly caffeinated. What? Caffeine is an appetite suppressant? Well, yes it is. I'm glad you raised that concern. It's also a central nervous system stimulant, which causes your body to produce and release more hormones like Cortisol (which tells your body to store food as fat) and Insulin (which we all know is the devil!) Therefore, you're more likely to eat more overall if you're highly caffeinated, even though it's an appetite suppressant.

Stevia gives me a headache, and sugar alcohols are... problematic. They have a lot of side effects.