Now this actually easier for Muslims but if you are a non Muslim, you can do it too. Why is it easy for Muslims? Every year for a whole month there comes a month of Ramadan where an average person performs Fasting. They go without food and water or any thing that might break their fast from Dawn till Sunset (check your local timings). Now this has proven to be very effective for the body and according to recent studies, Fasting helps decrease the risk of Cancer and very incredible way to lose weight. It has many more health benefits that comes with fasting.
Now the golden time when you should be excersising is during your fast just an hour before breaking your fast.
Now see, when you excerccise while fasting, it forces your body to shed fat, since the body's fat burining processes are controlled by the sympathetic nervous system (SNS), and the (SNS) is activated by the excersise and lack of food
Exercise and fasting together also yields heavy increases in oxidative stress, which actually benefits your muscle
If your workout includes heavy lifting, it is very important to eat within 30 minutes after your workout, and your meal should include good amounts of protein.