Most people who do 5:2 intermittent fasting consume about 500-600 calories 2 days per week and eat normally the other 5 days. If one of your goals is weight loss, depending on your caloric needs, this should support 0.5-1 pound of weight loss per week. If you do 5:2 fasting, it's essential to ensure you eat high-fiber meals and adequate protein on non-fasting days.