I can't speak to the sore throat but I do keto and on days I skip most/all food, I get crazy food cravings that can usually be addressed (provided I'm not recently re-entering keto but am a week+ fat-adjusted) by drinking a bottle of water with a squirt of electrolyte replacement concentrate (K+Mg) along with 3-5g of salt.
I normally eat a pretty high-salt diet (7-10g per day depending on if I eat out or not), keto or no, and replacing a day's salt with just 1-2g is insufficient to keep my body from cravings. I find that having 3-5g with my other misc electrolyte replacement generally makes it much, much easier for me to skip the day's meals.
Cravings are almost always your body asking for something; the trick is to learn what it's asking for that doesn't involve calories.
I normally eat a pretty high-salt diet (7-10g per day depending on if I eat out or not), keto or no, and replacing a day's salt with just 1-2g is insufficient to keep my body from cravings. I find that having 3-5g with my other misc electrolyte replacement generally makes it much, much easier for me to skip the day's meals.
Cravings are almost always your body asking for something; the trick is to learn what it's asking for that doesn't involve calories.