I HAVE FASTED for three days (twice). I have fasted quite a few times for just one day and once for two days. And even though fasting is sometimes difficult, it has improved my mood overall, and the research seems to indicate it improved my health too.
A recent study found that those who fasted one day per month were 40 percent less likely to have clogged arteries. That's a pretty big difference.
Almost always, if something is good for your health, it's also good for your mood, and this is no exception. If you've never tried it, I recommend a simple one-day fast.
Do it on a day off (you may not feel very energetic). Don't eat anything at all from the time you get up in the morning until the following morning. Don't drink anything except water, and drink plenty of water. You will be thirsty. Don't do a lot of strenuous activity. Just take it easy and relax, but keep yourself busy on tasks that don't require a lot of physical energy.
If you normally drink coffee, stop drinking it a few days before your fast so you are over your withdrawals before you begin fasting.
At times, fasting doesn't feel good, but it is surprisingly easy, even for someone like me who usually never even considers skipping a meal. Occasionally throughout a fasting day, you'll feel really hungry. And then it goes away and you get involved in what you're doing and forget about food.
The most amazing thing is how much time you have when you're fasting. A day without food seems twice as long, and not because you're suffering. It's because food preparation and eating the food takes a lot of time.
Anyway, I recommend it. You'll appreciate food more in the days following a fast, you'll be in a better mood, and you'll be healthier.