I noticed if one is healing most of saturation is going to be lost. I looked up for an option to turn this off. I remember that this is not the case in 1.7.10. I don't know if it is a bug.

I turned this to true. But it hasn't any effect on this.
Disable the hunger drain when healing that was introduced in vanilla 1.6.2 [vanilla: false] [default: true]
B:disableHealingHungerDrain=true

The problem is that it is causing healing to be slower but one is not able to eat, because of "Well Fed" effect.