How Long Does Intermittent Fasting Take To Work?

Fact Checked

We believe information about products and services that could benefit people should be made available to consumers to help them make informed decisions about their health care. Therefore, we try to provide accurate and reliable information by working with different fact-checkers to review articles for factual accuracy, relevance, and timeliness. A team of qualified and experienced fact-checkers rigorously reviewed our content before publishing it on our website. At TnHealth, we rely on the most current and reputable sources cited in the text and listed at the bottom of each article. Content is fact-checked after it has been edited and before publication.

Updated on - Written by
Medically reviewed by Kathy Shattler, MS, RDN

How Long Does Intermittent Fasting Take To Work

Many people practice intermittent fasting for weight loss and to live a healthier lifestyle. But, how long will it take for you to see any intermittent fasting results when on this diet?

Frankly, you have to wait about ten weeks to see intermittent fasting results. It’s different from a normal diet, and research shows it has exceptional health benefits[1] to the body.

Not to mention that you get to lose significant weight during this period. This article teaches more about intermittent fasting and how long it takes to work. It also explores the health benefits of an intermittent fasting diet.

How Long Does Intermittent Fasting Take to Work?

Losing weight is among the top goals of people seeking a healthier lifestyle. Many are now turning to intermittent fasting to achieve a healthy weight. This diet involves a fasting period where you don’t take any food and cyclic eating periods where you consume a healthy diet.

The excellent news is that there are no food restrictions with this diet, only rules on when is the right time to eat. Hence, this eating pattern moves away from the normal diet, but this isn’t a free pass to eat junk food. It’s better to stick with healthy foods during the eating periods.

When you choose to participate in intermittent fasting, you can fast from 16 to 24 hours. This isn’t something new, as people have been engaging in fasting for centuries. Since it took time to find food, people could last for long periods without eating any food.

With that in mind, how long does intermittent fasting take to work? Truthfully, it takes time[2] to experience fat loss, so give yourself about ten weeks. During this period, certain changes occur, making it easier for your body to burn fat.

How Does Intermittent Fasting Affect the Body?

For many people, intermittent fasting is the best way to achieve weight loss. But, how does it affect the body? How can you achieve the best intermittent fasting results?

Intermittent fasting significantly impacts the body’s molecular and cellular structures. When you start this process, your hormone levels shift to permit your body[3] to burn fat. The body stores the fat in different areas, and only by accessing them can you achieve significant weight loss.

In addition, having a fasting period makes it possible for cell regeneration and repair. Intermittent fasting works to help you achieve fat loss. Another significant change that takes place is improving insulin sensitivity.

When you begin intermittent fasting, your body has lower insulin levels and fewer blood sugar problems. As a result, the fat stores all over your body are easily accessible[4]. This is how you manage to achieve significant weight loss throughout the fast.

Also, intermittent fasting makes it possible for the body to achieve significant cellular repair. During this period, autophagy takes place[5]. Autophagy removes old cells and dysfunctional protein anywhere inside the human cells.

An intermittent fast can even impact your gene structure in a few weeks. That way, you’re less likely[6] to be susceptible to certain illnesses. There’s significant change and improvement in your overall health while working towards a healthy weight. 

Ways of Doing Intermittent Fasting

Intermittent fasting involves an eating window and fasting window. It’s best to speak with a licensed nutritionist about the best intermittent fasting method to begin with. This approach is different from the many diets you encounter when you want to lose weight.

Significant weight loss is possible when you cut extra calories from your diet. You have an empty stomach during the fasting window and can only drink water. Later, during the eating window, take healthy foods, including healthy fats, lean protein, whole grains, fruits and vegetables, and leafy greens.

That way, you have enough calories to keep you going but can also begin the weight loss process. Below are some of the intermittent fasting methods to try:

16/8 Methods

The 16/8 method is one of the most popular among people who engage in intermittent fasting. It involves an eating window of 8 hours and a fasting window of 16 hours. This method can help you achieve intermittent fasting results in a few weeks.

It requires calorie restriction during the eight hours when you can eat, so it’s better to work with a meal plan. The benefits of intermittent fasting are evident when you eat enough calories and engage in physical activity.

5:2 Diet

You can only consume a maximum of 600 calories for two days of the week for this method. After that, you can follow a normal diet for the remaining five days.

Instead of food, take lots of water for the two that require restricting calories throughout the day.

Eat-Stop-Eat

Fast for 24 hours once or twice a week. A good example is eating lunch as the last meal and skipping dinner plus other meals until the next evening. That way, your first meal after the fast will be dinner the following day.

Fasting for such long periods requires resilience and advice from licensed nutritionists. When you fast, you can drink water throughout the day. You need to eat healthy fats, lean protein, whole grains, fruits, and leafy greens during the eating window. That’s enough calories to aid you in losing weight.

Health Benefits of Intermittent Fasting

Intermittent fasting takes some time to work. During that period, you can enjoy several health benefits. These include

Weight Loss

An intermittent fasting diet can help you burn fat and improve your overall health. In fact, a huge percentage of people trying this diet do so to shed body fat. Thanks to fasting and eating a balanced diet, weight loss is quite possible.

Not only do you have a lower caloric intake, but your hormone levels also shift to facilitate weight loss. These hormonal changes significantly impact[7] your metabolic rate, thus facilitating body fat loss.

Fat accumulates in the body when you have a high-calorie intake, including eating lots of junk food. But, when you begin to fast and eat healthy foods with enough calories, losing weight is easier to accomplish. The eating period allows you to take enough nutrients to keep you healthy.

But, when you go for extended periods without eating food, your body burns more calories. For example, when you eat for 8 hours and fast for 16 hours, your body starts to use up the fat stores. In a few weeks, you start to notice your body getting leaner.

Frankly, significant scientific evidence shows fasting intermittently is an effective way[8] to achieve significant weight loss.

Reduce Insulin Resistance

Insulin resistance can have a huge impact on your overall health because it leads to many health conditions. Thankfully, intermittent fasting helps reduce blood sugar problems while on a health journey.

Intermittent fasting helps to lower insulin levels by up to 31%, protecting your body[9] from health conditions.

But, it’s better to consult a health care provider before you start an intermittent fast. They can guide you on the best way to fast for long periods without affecting your health. Also, you get advice on balanced diets so that your body gets enough nutrients.

Reduce Inflammation Markers

Inflammation does help the body protect and defend itself, but it can also have a negative effect. When you experience chronic inflammation, you might encounter a host of health problems. These health conditions can affect your overall health.

Thankfully, intermittent fasting works in many ways to benefit the body. For instance, as you work on restricting calories, you also reduce inflammation markers in your body. As a result, studies suggest the chances of experiencing these health conditions drop significantly[10].

Improve Heart Health

In animal studies, poor heart health is closely related[11] to weight gain. Chronic heart ailments are high when overweight or are obese. Luckily, fasting for long periods can help you tackle this issue and cut extra calories in the process.

Intermittent fasting works to reduce LDL (bad) cholesterol and blood pressure in the body[12]. It also helps to achieve low blood pressure, reduce inflammation markers and increase insulin sensitivity. By tracking your caloric intake and fasting for extended periods, you can lose weight and improve your heart health.

Summing Up

Losing weight is quite important because it has many health benefits for your body. People use many diets together with physical activity to achieve weight loss. Today, one of the most popular is the intermittent fasting diet.

It entails eating for a set period and going on an empty stomach for the remaining time. Intermittent fasting shares similarities to the warrior diet, where you eat less or no food for extended periods. As a result, you can enjoy many health benefits, including lower insulin levels, weight loss, and better heart health.


+ 12 sources

Tnhealth has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We work mostly with peer-reviewed studies to ensure accurate information. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

  1. Longo, Valter D. and Mattson, Mark P. (2014). Fasting: Molecular Mechanisms and Clinical Applications. Cell Metabolism, [online] 19(2), pp.181–192. Available at: https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3946160/ [Accessed 11 Feb. 2022].
  2. ‌Tello, M. (2018). Intermittent fasting: Surprising update – Harvard Health. [online] Harvard Health. Available at: https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156 [Accessed 11 Feb. 2022].
  3. ‌Blackman, M.R. (2002). Growth Hormone and Sex Steroid Administration in Healthy Aged Women and Men. JAMA, [online] 288(18), p.2282. Available at: https://pubmed.ncbi.nlm.nih.gov/12425705/ [Accessed 11 Feb. 2022].
  4. ‌Heilbronn, L.K., Smith, S.R., Martin, C.K., Anton, S.D. and Ravussin, E. (2005). Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. The American Journal of Clinical Nutrition, [online] 81(1), pp.69–73. Available at: https://pubmed.ncbi.nlm.nih.gov/15640462/ [Accessed 11 Feb. 2022].
  5. ‌Kim, I. and Lemasters, J.J. (2011). Mitochondrial degradation by autophagy (mitophagy) in GFP-LC3 transgenic hepatocytes during nutrient deprivation. American Journal of Physiology-Cell Physiology, [online] 300(2), pp.C308–C317. Available at: https://pubmed.ncbi.nlm.nih.gov/21106691/ [Accessed 11 Feb. 2022].
  6. ‌Martin, B., Mattson, M.P. and Maudsley, S. (2006). Caloric restriction and intermittent fasting: Two potential diets for successful brain aging. Ageing Research Reviews, [online] 5(3), pp.332–353. Available at: https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2622429/ [Accessed 11 Feb. 2022].
  7. ‌Zauner, C., Schneeweiss, B., Kranz, A., Madl, C., Ratheiser, K., Kramer, L., Roth, E., Schneider, B. and Lenz, K. (2000). Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine. The American Journal of Clinical Nutrition, [online] 71(6), pp.1511–1515. Available at: https://pubmed.ncbi.nlm.nih.gov/10837292/ [Accessed 11 Feb. 2022].
  8. ‌Welton, S., Minty, R., O’Driscoll, T., Willms, H., Poirier, D., Madden, S. and Kelly, L. (2020). Intermittent fasting and weight loss: Systematic review. Canadian family physician Medecin de famille canadien, [online] 66(2), pp.117–125. Available at: https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7021351/ [Accessed 11 Feb. 2022].
  9. ‌Albosta, M. and Bakke, J. (2021). Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Clinical Diabetes and Endocrinology, [online] 7(1). Available at: https://pubmed.ncbi.nlm.nih.gov/33531076/ [Accessed 11 Feb. 2022].
  10. ‌Abeyasekera, K.N. (2020). Benefits of Intermittent Fasting: A Systematic Review of Randomized Clinical Trials. [online] Dominican Scholar. Available at: https://scholar.dominican.edu/physician-assistant-studies-student-articles/12/ [Accessed 11 Feb. 2022].
  11. ‌Akil, L. and Ahmad, H.A. (2011). Relationships between Obesity and Cardiovascular Diseases in Four Southern States and Colorado. Journal of Health Care for the Poor and Underserved, [online] 22(4A), pp.61–72. Available at: https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3250069/ [Accessed 11 Feb. 2022].
  12. National Institutes of Health (NIH). (2015). Benefits From Lower Cholesterol and Blood Pressure Targets. [online] Available at: https://www.nih.gov/news-events/nih-research-matters/benefits-lower-cholesterol-blood-pressure-targets [Accessed 11 Feb. 2022].

Medically reviewed by:

Mitchelle Morgan is a health and wellness writer with over 10 years of experience. She holds a Master's in Communication. Her mission is to provide readers with information that helps them live a better lifestyle. All her work is backed by scientific evidence to ensure readers get valuable and actionable content.

Medically reviewed by: