How and what do you feed to the NPCs to enslave them.
Tips for Liquid Food
Broth – Meat, water (waterskin) and a bowl.
Place in their inventory and press E to use it.
Also, for good measure, after I give them a bite of broth, I put a bandage on them and use it to quickly boost their health.
If you get attacked (like by rabid dogs) on the way back to your place while carrying the NPC and have to put him or her down, the extra health will help because the dogs will attack the NPC.