500 or 800 calories on intermittent fasting?

The most frequent question about intermittent fasting is about how many calories you should eat on a fasting day (FD). Should it be 500 or 800 calories on intermittent fasting?

The answer actually depends on your gender, how much you want to lose and how fast. Each pattern of intermittent fasting calls for different eating windows or calorie numbers.

500 calories

Intermittent fasting at 500 calories per day is related to the pattern called 5:1 or 5:2. This means you eat 5 or 6 days per week what you like and one day or two days per week you limit your calorie intake to 500 calories for a female and 600 calories for a male.

500 calories do not seem like much but it actually keeps you sustained well. You can spread the 500/600 calories over either one, two or three meals per day.

Way too many voices out there claim intermittent fasters can eat whatever they like. I believe that it’s actually incorrect as we should always try to eat the best food we can. That said, obsessing about it is not healthy either. There should always be a good balance between the physical and mental state when we change our lifestyle. That’s why many diets fail. We obsess too much and often give up.

We all know what is healthy and what is not. We should try to eat lean meats, limit the intake of unhealthy fats and sugars, especially on fasting days. Give vegetables and fruit a go and prepare your meals whenever you can. Home cooking will help you lose weight faster and the nutrition you get is of better quality.

healthy food on intermittent fasting

To maximize our nutritional intake is very important. As we count calories on 5:1, 5:2 or 800 patterns, the food intake is low. We have only one, two or 3 small meals per day. Our body needs nutrients to function well, to get the required minerals and vitamins, healthy fats and fiber. It’s vital we give out body good food. It will start functioning better and reward us with weight loss.

On the non-fasting days, it is ok to eat pretty much what you like and you don’t have to count calories. This has proven useful to some but some people still need to work out what is the best intermittent fasting pattern for them and eat good food.

Many people, like me, overeat, trying to catch up with whatever they have not eaten on those fasting days. I started on the 5:2 fasting pattern and lost weight. I switched to the 16:8 pattern and found it easier and lost more weight.

The 500/600 calorie fasting days call for reading nutritional information on the labels, weighing your food, checking calorie count in each ingredient and stick to it. A good set of scales should do the trick with an application such as My fitness pal to help you track your calories.

Bring your diary out and make sure you don’t go over the calorie limit. You can have for example breakfast of 100 calories, lunch of 200 calories and then 200 calories for dinner if you are a woman. Or if you just prefer to have one meal of 500 calories, that’s fine too.

800 calories

800 calorie fasting follows the 500 calorie pattern. As the number indicates, you eat 800 on your fasting days. Originally, it was 500 calories according to research by Dr. Michael Mosley who is the initiator of intermittent fasting in his recent research.  

According to Mosley, it is much more manageable to eat 800 calories per day and still lose weight and makes it much more manageable for people to maintain it. It follows exactly the same pattern as the 5:1 or 5:2 when you fast once or twice a week at a maximum of 800 calories. As it is with 500 calories per day, you need to be quite diligent and measure your calorie intake not to exceed 800 calories on fasting days.

800 calories for rapid weight loss

800 calories for rapid weight loss is an Intermittent Fasting plan developed by Michael Mosley. He claims that to give you motivation and to lose weight faster, it’s good to stick to 800 calories per day for at least two weeks.

To see results means that every day of the week you need to be meticulous and measure calories. You cannot exceed 800 calories per 24 hours. It seems like a dramatic approach but it is a short term. You can see great results in losing weight and become motivated to continue with a different pattern of Intermittent Fasting afterward.

800 calories for rapid weight loss can benefit a motivated person who is determined not to exceed smaller food intake for a longer period of time. We are talking weeks, not months.

The best way to go about it is to cut out sugar and alcohol, limit fat and eat nutrient-dense food. Although you can eat what you like, you will soon realize that healthy food fills you up more and you naturally avoid junk food.

What’s better, 500 or 800 calories on intermittent fasting?

Intermittent Fasting at 500 or 800 calories? That’s an interesting question and it is very individual.  Practicing the 500 calories it’s probably more beneficial on one or two days per week if you don’t have experience with intermittent fasting and have the willpower to do it. 

If you’re just starting and you really want to try one or two days per week and not sure about the food, quantities and may be very hungry at 500 calories, 800 calories would be enough just to see how you can manage.

It’s good to start at 800 calories. You can always cut back later so you can for example do 800 calories one time or two times per week on two non-consecutive days. See how you feel try to do it for two weeks and see how you feel and how your body reacts. If it’s manageable for you, bring it down to 500 calories after two weeks.  If counting calories is not for you, there are other better patents of intermittent fasting where you don’t have to count calories such as the 16:8 or the 12:12. Those are great for complete beginners.


I found the key to a healthy weight loss is through eating good food at the right time and managed to lose wight only by popping those calories after having tried numerous diets out there.

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