I like them a lot. I use my own mix (which has much higher potassium) at home and LMNT packets while on the go, and also snake juice packets. I think if I were to go LMNT only id be concerned about potassium intake (and cost lol).
Only the flavored ones have calories (and stevia). Get the unflavored ones for fasting support.
I once went for a 30 day fasting only on lmnt. Its was great but around 10-12th day, I got sick of the flavor. I’d almost get gag reflex when I drink it. If you plan on going for such long fasts, I’d suggest going for unsweetened one. My weight loss also seemed low when compared to other people who were prepping their own mix.I know everyone’s different but after 30 days I barely dropped 40 pounds and that’s before I started to refeed. It does taste good and I’d still recommend it for shorter fasts. Even 7 day fasts should be fine.