Fasting uniquely places our physical, emotional, and spiritual capacities under the same burden. This means that the effects of fasting will affect each of these areas. As a disclaimer, please contact your physician before attempting a food-based fast if you have a medical condition. Here are some common effects fasting may have on you:
Physical
Changing your food intake, especially completely abstaining from meals, will challenge your body. It is likely that you will feel fatigued and intensified hunger. Headaches are another common symptom.
Emotional
Eating is connected to our emotions, so we should not be surprised that fasting will expose some negative emotions. Be prepared for heightened emotional sensitivity and responses like anger and irritability.
Spiritual
Fasting is an earnest act of submission to and dependence on the Lord. Positively, it positions us to be more sensitive to the conviction and leading of the Spirit. Times of fasting are often marked by repentance.
Also, be mindful of the enemy's schemes–you will experience heightened temptation and discouragement if you aren’t clearly seeing answers to your devotion and prayer.