Jacob was simply a perpetually happy person, and he carried this happiness with him like an aura, sharing it with whoever was near him. Lika an earthbound sun, whenever someone was within his gravitational pull, Jacob warmed them. It was natural, a part of who he was.
I always thought eating was a ridiculous activity anyway. I'd get out of it myself if I could, though you've got to do it to stay alive, they tell me.