I know a lot of people know this but for the people that don't, when an RG eats a quart so he gets a healing buff that drains hunger quickly. Now I'm going to tell you how to use this to your advantage, when your RG starts to torpor run, kill small Dino that you can drag and drag it to your RG so that it eats it and then try to knock it out in the amount of time that it has its healing buff, around 20 second. Once you have knocked out your RG put your tanning food in and it will quickly eat it. because it's food is drained almost completely, if you aren't able to knock it out in this duration of time does timing method won't work.

I hope this was helpful