Intermittent Fasting Side Effects, Methods, Precautions, And More

Medically reviewed by Maria Sarino, MD FACT CHECKED

These days, as people are becoming more health and fitness conscious, they are looking for different methods: intermittent fasting.

Have you ever wondered what intermittent fasting is and why you should try it? Here, I have talked about the basics of Intermittent Fasting and the side effects.

As intermittent fasting is a restrictive eating pattern it is not healthy for all and could show some potential side effects on people, it is important to figure out which type is best for your body.

We have mentioned a few of the intermittent fasting side effects below.

  • May Cause Overeating

    A few of the intermittent fasting techniques are based on eating for some time and then fasting.

    This may likely increase your urge to eat more during the eating phase as you may crave food in the fasting phase in the initial time till your body is adjusted to your new schedule.

  • Low Energy

    Eating less or more restrictive could lead to slow metabolism and your body may not be able to gain much energy to make you feel energetic.

    In some people, it could also cause disturbance in their sleeping pattern which will affect tiredness and laziness all day.

  • Constipation

    During intermittent fasting, you may get some symptoms related to the stomach such as bloating, diarrhea, digestion issues, etc.

    Diarrhea may be caused due to eating more in less time and this is in one of the regimes of IF, other symptoms are mostly due to lack of water in your body or food intake.

  • Lack Of Nutrition

    Our body needs a fixed minimum amount of nutrients daily which comes from food intake.

    If we fast for a long period or do restrictive food intake our body could not get enough nutrients which could lead to health complications. Try to have a nutritious diet in small amounts whenever you eat before and after fasting.

  • Rise In Irritation

    Intermittent Fasting could lead to low blood sugar level which may make you feel irritated, the other reason for rising in irritation may be the continuous feeling of starvation and craving for some good food.

    This could also lead to poor concentration in doing things and you may become more anxious throughout the day.

  • Dehydration

    The process known as natural diuresis occurs in the initial days of Intermittent Fasting when your body releases more water and salt in urine which could make your body dehydrated.

    Some people also have a habit of having a glass of water before or after their meal, if they skip a meal they also forget to have water. To prevent your body from dehydration add electrolytes to your glass of water.

  • Not Good For People On Medication

    Some medicines require a balance of nutrients during their course, even some medicines are suggested by doctors to be taken before/after meals. Being on medication while fasting could be a real challenge.

Although there is no proper research about the long-term risk of intermittent fasting for some people, health practitioners suggest avoiding doing Intermittent Fasting are

  • Pregnant women, breastfeeding women
  • Old age people with severe diseases like diabetes
  • People having immunodeficiencies
  • Young children
  • People recently had some surgery or operation
  • People having an eating disorder

What Is Intermittent Fasting?

It is a cycle of eating between periods of fasting and eating with more focus on when you are eating rather than what you are eating. It is a regular schedule of eating during a specific time.

It has been scientifically proven that intermittent fasting could help in reducing not only weight but also helped in preventing some forms of diseases.

In the 1940s, laboratory experiments on mice showed that calorie restriction in form of Intermittent Fasting extended the animals’ life span without leaving it malnutritional.

Common fasting has been done by humans for a long involving day-time fasting and night meals for religious or spiritual reasons.

Methods Of Intermittent Fasting

Many Intermittent Fasting methods may help you in weight loss or have their benefits. Most people schedule 8 hrs period of eating during the day and fast for the remainder, also known as the 16:8 approach.

Below are mentioned most common methods used but you must check first if your body is capable of doing the Intermittent Fasting or not.

  1. 5:2 Approach 

    It involves limiting yourself to one 500-600 calorie meal for two non-consecutive days a week.

    For example, you eat normally 3 meals a day every day of the week except Tuesday and Friday.

    It may also include one meal of 500-600 calories. Within a month it is seen that the body gets accustomed to the fasting method and you won’t feel hungry on the fasting days anymore.

  1. Eat-Stop-Eat

    It involves fasting for 24 hrs and starting it from the evening of a day till the evening of the next day.

    It could be done once or twice a week and you may drink any non-calorie drink in between the schedule.

  2. Warrior Diet

    It is based on the eating pattern of warriors in ancient times when they were able to eat less during the day and have their proper meal at night.

    In this food from the supermarket and plastic box contained are avoided and only healthy and organic food is preferred.
  3. Lean Gains

    It is also known as 16:8 as mentioned above in which you eat between 8 hours and fast for the remaining 16hrs.

    For better results, you could also skip breakfast and could start from brunch time to evening.

Precautions To Be Taken While Intermittent Fasting

Calorie restriction in your body using these above-mentioned methods may help you in improving the health of your body and brain.

Intermittent fasting has become a popular way to lose weight and improve health. However, there are some things you need to be aware of before you start intermittent fasting.

  • It is important to talk to your doctor before starting any new diet or fitness regime. This is especially important if you have any medical conditions or are taking any medication.
  • When intermittent fasting, you will be restricting your food intake for periods. This can put your body under stress and may not be suitable for everyone. If you are pregnant, breastfeeding, or have any other health concerns, please speak to your doctor before starting intermittent fasting.
  • It is also important to listen to your body when intermittent fasting. If you feel faint, dizzy, or weak, stop fasting immediately and eat something. It is also important to drink plenty of water when IF, as this will help to keep your body hydrated.

Overall, intermittent fasting is a safe way to lose weight and improve your health. However, it is important to take precautions and speak to your doctor before starting this type of diet.

As Intermittent Fasting has its benefits but if someone overdoes it, it can be harmful and can affect different males and females.

For precautions, you must visit your health professional for the method which will suit your body and doctor if you have any uneasiness in your body.

Risks Related To Intermittent Fasting

As Intermittent Fasting has its benefits but if someone overdoes, it could be harmful and may affect different males and females.

Some people could have headaches or feel dizzy during the fasting time as their body doesn’t allow them with sudden reduction of calorie intake.

For precautions, you must visit your health counselor for the method which will suit your body and doctor if you have any uneasiness in your body.


As you are reading this. By now you must be aware of everything about intermittent fasting. These may help you in maintaining your overall lifestyle.

It could also improve your metabolism and could also give your body maintain its health quotient in between meals throughout the day.

I hope you may get the desired physique when you consider Intermittent fasting as your diet pattern and could control your cravings.