In general, hunger and irritability are the main side effects experienced during intermittent fasting. These effects are usually temporary - the time it takes for the body to adjust to the new meal schedule. Staying hydrated will help, so be sure to drink plenty of water, herbal teas, and even black coffee. It should be noted that intermittent fasting is not for everyone and you should consult a health care practitioner first to find the formula that is best for you.