I played this game for a while and got curious about microwave. Do you need to microwave the MREs to make it give yo more hunger? And what is the perfect time to microwave your food so it has all bonuses and doesn't get too hot.

You don't really need to microwave MRE's, as they stay good for quite a while. I usually don't cook stuff for too long and usually get good enough hunger back from most things. However, if you want to know when would be a good time to heat things up, you can buy a thermometer to see how cold a piece of food is.

Microwaved food does give you more hunger points. Freezed food you can microwave for around 30 seconds to get most hunger points, normal food you can microwave for 15 for it to not get too hot, that is at least for 0.6.3 update, things may be changed slightly in 0.7.0