Symptoms That Indicate You Need To Stop Fasting + How To Fast Properly

Know how to listen to your body before you make any drastic dietary changes.

Medically Reviewed by Madhu Sharma, RD
By Shaheen Naser

Fasting is a method that most people practice for quick and effective results. While fasting comes with its set of benefits, it’s certainly not for everybody. If you show signs of tiredness, discomfort, and sickness, this is definitely your body giving you signs to stop fasting. In this article, we take you through how to fast safely and a few signs that suggest that you need to stop fasting.

Symptoms That Indicate You Should Stop Fasting

Every individual looking forward to losing weight intends to fast until they shed those excess pounds. But not all can go through the fasting phase smoothly. If you are on a fasting spree and notice any of the following symptoms, you need to stop fasting:

  • Dizziness
  • Loss of consciousness
  • Nausea and vomiting
  • Diarrhea
  • A burning sensation in the stomach
  • Chest pain or stomach pain
  • Menstruation
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Keeping your fasting periods short is important because more extended periods may lead to fainting, dehydration, and dizziness.

Once you regain your energy, you can get back to fasting. The following tips will help you ensure you fast safely.

How To Fast Safely

1. Stay Hydrated


Individuals on a fast are likely to feel dehydrated. About 20 to 30% of the body’s fluid requirements are met through food, and fasting can alter this (1). Hence, it is important that you drink lots of water and stay hydrated while fasting.

2. Restrict Your Calorie Intake


Fasting usually involves staying away from all foods/drinks for a period. However, instead of eliminating all sources of food, you can reduce your calorie intake on the days of fasting. This way, you will only consume 25% of your daily calorie requirements for two days a week to facilitate weight loss (2).

Did You Know?
There are different types of fasting, like intermittent fasting, water fasting, juice fasting, calorie restriction, and partial fasting.

3. Do Not Feast While Breaking The Fast

As tempting as it may be to feast on all your favorite savories while breaking your fast, you should not do so. Feasting on a lot of food can leave you feeling instantly bloated and tired. It can also slow down the weight loss process as it will reduce the calorie deficit (3).

4. Keep The Exercises Mild


When you are on a diet, your body runs low on energy. Hence, keep your exercises mild. Indulge in strenuous workouts only on the days you aren’t fasting. As your body gets used to exercising, you can gradually start trying out high-intensity workouts to increase the utilization of the stored fat in your body (4).

5. Take Additional Supplements


When you fast, you tend to miss out on a lot of nutrients essential for your body. People on a diet are deficient in a number of nutrients – including calcium, iron, and vitamin B12 (5). You can make up for these deficiencies by taking a nutritional supplement after consulting your healthcare provider.

6. Eat Whole Foods During Non-Fasting Days


It is important you eat whole foods on non-fasting days. This not only prevents deficiencies but also cuts the risk of severe illnesses like heart disease and cancer (6).

7. Eat More Protein


Consuming more protein is a necessity not only while working out but also when you want to lose fat and build muscles. Increase your intake of protein-rich foods like chicken, eggs, cheese, fatty fish, and nuts during the period you are not fasting (7).

While fasting once in a while can help cleanse and detox your system, you should not overdo it. Dizziness, nausea, vomiting, chest pain, or irregular menstruation are all signs to stop fasting. Staying well hydrated, with ample supplements, mild exercise, and restricted calorie intake can help you fast in a healthy and more effective way.

Frequently Asked Questions

Is it normal to throw up while water fasting?

Throwing up or vomiting is one of the many indicators that you need to give fasting a break for some time. Hence, if you throw up on a water fast, it is best to start eating something until you are healthy enough to continue fasting.

When should I quit water fasting?

If you experience any symptoms like vomiting, nausea, dizziness, loss of consciousness, diarrhea/constipation, or abdominal pain, you should stop fasting immediately.

Can fasting make you sick?

Yes, fasting can cause dehydration, which may lead to other undesirable consequences.

Is it safe to fast for 3 days?

You can fast safely for 2-3 days without experiencing any adverse health effects (8). But, we suggest you prepare your body for water fasting by consuming fewer foods on the days prior.

What not to eat after fasting?

You should not binge on junk foods or other saturated foods after fasting. This may affect your weight loss progress by disrupting the calorie deficit you have created.

Who all should not fast?

People with diabetes, cardiac, or renal problems or on medicines for any medical conditions should avoid fasting. Pregnant and lactating women should also avoid fasting.


  1. Contribution of Water from Food and Fluids to Total Water Intake: Analysis of a French and UK Population Surveys” Nutrients, US National Library Of Medicine, National Institutes of Health.
  2. Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults.” American Journal Of Clinical Nutrition, US National Library Of Medicine, National Institutes of Health.
  3. Diet in the management of weight loss” Canadian Medical Association Journal, US National Library Of Medicine, National Institutes of Health.
  4. Metabolic responses to exercise after fasting.” Journal of Applied Physiology, US National Library Of Medicine, National Institutes of Health.
  5. Prevalence of micronutrient deficiency in popular diet plans” Journal Of The International Society of Sports Nutrition, US National Library Of Medicine, National Institutes of Health.
  6. Mediterranean Diet and Prevention of Chronic Diseases” Nutrition Today, US National Library Of Medicine, National Institutes of Health.
  7. Preserving Healthy Muscle during Weight Loss” Advances in Nutrition, US National Library Of Medicine, National Institutes of Health.
  8. Is fasting safe? A chart review of adverse events during medically supervised, water-only fasting” BMC Complementary and Alternative Medicine, US National Library Of Medicine, National Institutes of Health.

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Shaheen holds a postgraduate degree in Human Genetics and Molecular Biology from Bharathiar University. She is a Geneticist with proficiency... more

Madhu Sharma

Madhu Sharma is a member of the National Executive Committee of IDA. She has been associated for almost three decades... more