I had no problem fasting for 48 hours after I went to the dentist to have my teeth cleaned...
If you already eat once a day on a regular basis, I'm surprised you're having trouble going 36 hours. It might just be mental and you think you're hungry. I like the ZC rule: Does a steak sound good? Yes? Then you're hungry
Or find something to distract yourself? Get out and socialize, visit a museum, work on a project of some kind.
Also, when you do break the fast, I'd eat slowly and pay attention to my satiation. Most advice I've seen has said to not try to make up for food you missed -- just eat a normal sized portion, or until your appetite is satisfied. This also has worked a lot better for me than "eating big" after skipping meals.
Give me a friendly Christian any day over an asshole atheist.