I have that happen. I daydream about food. I look at menus online even though I know I can’t eat anything. Just goes to show how powerful the psychological component of hunger is.
Don’t worry is you appear to be obsessed with food. Stay within yourself and don’t cave. This is the important part.
Happens to me too around 48h of a fast. It only shows that physically fasting itself is easy but the mental battle is what makes it hard.
I’m not sure if there is any way to stop it tho. As you said its a biological response. I always try to avoid food topic as much as possible. And drinking water helps a lot too.