How Long Until Intermittent Fasting Works? A Realistic Timeline for Results

From weight loss to improved energy, find out how to optimize your fasting journey to see quick results.

Dr. Rashmi Byakodi
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Dr. Rashmi Byakodi
Dr. Rashmi Byakodi is a health and wellness writer who aims to spread awareness about health through her words. With her medical background and a passion...
| Updated by Ash, ACE, MSc
11 Min Read
How Long Fasting Results
How Long Fasting Results

Intermittent fasting (IF) is well-known for its weight loss and health benefits. However, a frequently asked question is, ‘How long does it take to see results with intermittent fasting?’ Given the variety of approaches to IF, it’s understandable that this question arises.

As a health and wellness writer with a medical background, and having personally explored how IF can enhance health, including my sprinting skills, I’ll share insights into the effectiveness and timeline of seeing results with intermittent fasting in this article.

Key Benefits of Intermittent Fasting

When you practice intermittent fasting, you get a lot of benefits, both direct and indirect. Let us take a look at some of the important ones.

Enhancing Insulin Sensitivity

Intermittent fasting helps reduce insulin resistance. IF can lower blood sugar levels by 3-6% and reduce fasting insulin levels by 20-31%, playing a crucial role in preventing type 2 diabetes. [1]

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Weight Loss

Intermittent fasting is highly effective for weight loss, which is often the primary reason people try it. Unlike other diets, IF helps you lose weight without limiting your caloric intake.

Weight Loss Measuring Tape
Weight Loss

Reducing Inflammation

IF reduces inflammation, which is linked to chronic diseases such as cancer, high blood pressure, and high blood sugar. By managing inflammation, intermittent fasting helps better manage these conditions. [2]

Boosting Heart Health

Heart disease risk factors like insulin resistance, high blood sugar, LDL cholesterol, inflammation, and triglycerides can be reduced through intermittent fasting. [3]

Cancer Prevention Potential

Animal studies indicate intermittent fasting may prevent cancer. Although human studies are pending, the physiological similarities between lab rats and humans offer hope.

Enhancing Brain Health

IF boosts brain-derived neurotrophic factor (BDNF) hormone levels, promoting brain and nerve cell regeneration. This might help prevent cognitive diseases like Parkinson’s and Alzheimer’s.

Anti-aging Benefits

Intermittent fasting has shown to increase the lifespan of lab mice by 36-83%. It initiates autophagy, a process where the body restores and renews itself at a cellular level, which has anti-aging benefits. [4]

Choosing the Right Intermittent Fasting Regimen for Weight Loss

People primarily follow intermittent fasting for weight loss. Discipline is key to success. Start with shorter fasting windows and gradually extend them. Popular IF regimens include:

  • The 16/8 diet: Fast for 16 hours and eat during the remaining eight hours.
  • 23/1 (OMAD) Diet: Fast for 23 hours and eat in a one-hour window. [OMAD]
  • The 5/2 Diet: Eat normally for five days and restrict calories to 500-600 on two non-consecutive days. [5/2 diet]
  • Eat-Stop-Eat: Fast for a whole day once or twice a week. On non-fasting days, eat normally. [alternate day fast]

Many diets promise rapid weight loss but often result in the “yo-yo” effect. For sustained weight loss, intermittent fasting is effective. Consistency is crucial—make IF a lifestyle. The best results come from long-term practice.

If new to intermittent fasting, start with a 12/12 routine, fasting for 12 hours and eating three meals and snacks in the remaining 12 hours. Gradually transition to the 16/8 regimen. Small, steady steps prevent overwhelm and help your body adapt.

Realistic Weight Loss Expectations and Timeline

Several factors affect weight loss with intermittent fasting, including starting weight, medical conditions, diet during feeding windows, age, sex, activity levels, and lifestyle. Understanding these factors is crucial for setting realistic expectations.

For instance, intermittent fasting will not be effective if you consume processed food and sugary drinks during feeding windows. Pairing intermittent fasting with a balanced diet rich in whole foods is essential to achieve desired weight loss results.

A review of 40 case studies found intermittent fasting to be an effective weight loss tool, with individuals averaging significant weight loss over ten weeks. [5]

Other studies have shown weight loss ranging from 0.8% to 13% of total body weight over 2 to 26 weeks of alternate-day fasting. [6]

Research on the 5/2 IF regimen indicates weight loss results comparable to those achieved through traditional calorie restriction. [7]

Many people seek quick weight-loss solutions, but experts recommend a gradual approach. Aiming for a weekly weight loss of 1-2 pounds is both achievable and sustainable. This gradual loss helps ensure long-term success and minimizes the risk of muscle loss or nutrient deficiencies.

Weight Loss Expectations with Different IF Regimens
IF Regimen Expected Weight Loss Duration Study Reference
Alternate-Day Fasting 0.8% – 13% of total body weight 2 – 26 weeks [6]
5/2 Diet Comparable to traditional calorie restriction Varies [7]
General IF Practices Average weight loss over ten weeks 10 weeks [5]

Tracking Your Weight Loss Progress

Oversize Pants After Weight Loss
Don’t overly rely on scales to track weight loss; weight fluctuates daily. Weigh yourself at the same time each day, preferably in the morning. Use a measuring tape to track changes in your stomach, hips, and waist. A study showed women lost 4–7% of visceral fat with IF. [8]

Men generally see better weight loss results than women with IF. Women may lose up to 7 pounds in the first month, while men may lose 7-13 pounds.

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IF is most effective for those aged 42-48. Beginners in this age group might lose 20 pounds in the first month.

During the first two weeks, expect reduced bloating and a tighter midsection. Some see weight loss by week two, others in 4-6 weeks. Maintain discipline and dedication for best results.

Related: Water Fasting Weight Loss Calculator

Understanding Weight Loss vs. Fat Loss

Seeing weight drop on scales can be thrilling, but remember scales measure weight loss, not fat loss. Weight loss includes losing muscle, fluid, and fat. Focus on fat loss for overall body toning. Aim for 1-2 pounds of weight loss per week. Losing more than five pounds a week risks losing water weight, fat, and muscle, leading to nutrient deficiencies and dehydration. [9]
Speed Up Fat Loss

Reasons for Not Seeing Results with Intermittent Fasting

If 30 days have passed since starting intermittent fasting without visible changes, consider these factors:

  • Inadequate fasting times
  • Insufficient water intake
  • Frequent alcohol consumption
  • Not eating enough calories during feeding windows
  • Preference for processed food over healthy fats, lean proteins, and vegetables
  • Eating the same calories as before fasting
  • Following an unsuitable intermittent fasting schedule
  • Inadequate sleep
  • Overtraining
  • Lack of exercise

FAQs

How much weight can you lose in a month with intermittent fasting?

If you maintain a daily calorie deficit of 500 calories, you can lose one pound of body weight per week, resulting in 4-5 pounds per month.

How long does it take to see results from 12/12 fasting?

Experts say it takes ten weeks to see results with the 12/12 regimen, with an average weight loss of 7-10 pounds. Each person’s metabolism varies.

Does fasting for 16 hours burn fat?

Fat burning starts after 12 hours of fasting and intensifies between 16-24 hours.

Conclusion

Intermittent fasting is an effective weight loss method, but patience is essential. You didn’t gain weight overnight, and losing it will take time. Allow 4-6 weeks to see significant results. Consistency and patience will help you achieve your weight loss goals. Intermittent fasting requires dedication and diligence for the best results.
If you give it time and remain consistent, intermittent fasting will help you achieve your weight loss goals. Intermittent fasting is not a quick fix; it requires patience and diligence to deliver the best weight loss results.

References

Fitness Volt is committed to providing our readers with science-based information. We use only credible and peer-reviewed sources to support the information we share in our articles.

  1. Sathananthan, Matheni, et al. ā€œSix And 12 Weeks of Caloric Restriction Increases Ī’ Cell Function and Lowers Fasting and Postprandial Glucose Concentrations in People With Type 2 Diabetes.ā€ OUP Academic, 1 Sept. 2015.
  2. Alam, Iftikhar, et al. ā€œRecurrent Circadian Fasting (RCF) Improves Blood Pressure, Biomarkers of Cardiometabolic Risk and Regulates Inflammation in Men.ā€ PubMed Central (PMC), 19 Aug. 2019.
  3. Mani, Kartik, et al. ā€œLysosomes Mediate Benefits of Intermittent Fasting in Cardiometabolic Disease: The Janitor Is the Undercover Boss.ā€ PubMed Central (PMC), 14 Sept. 2018.
  4. Alirezaei, Mehrdad, et al. ā€œShort-term Fasting Induces Profound Neuronal Autophagy.ā€ PubMed Central (PMC), 14 Aug. 2010.
  5. ā€œDo Intermittent Diets Provide Physiological Benefits Over Continuous Diets for Weight Loss? A Systematic Review of Clinical Trials – PubMed.ā€ PubMed, 15 Dec. 2015.
  6. Welton, Stephanie, et al. ā€œIntermittent Fasting and Weight Loss: Systematic Review.ā€ PubMed Central (PMC).
  7. ā€œThe Effects of Intermittent or Continuous Energy Restriction on Weight Loss and Metabolic Disease Risk Markers: A Randomized Trial in Young Overweight Women – PubMed.ā€ PubMed, 1 May 2011.
  8. ā€œIntermittent Fasting Combined With Calorie Restriction Is Effective for Weight Loss and Cardio-protection in Obese Women – PubMed.ā€ PubMed, 21 Nov. 2012.
  9. ā€œGlycogen Storage: Illusions of Easy Weight Loss, Excessive Weight Regain, and Distortions in Estimates of Body Composition – PubMed.ā€ PubMed, 1 July 1992.
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Dr. Rashmi Byakodi is a health and wellness writer who aims to spread awareness about health through her words. With her medical background and a passion for writing, she has been creating health content on various platforms. She holds a dental graduate degree from Rajiv Gandhi University of Health Sciences and has worked in various hospitals for 5 years. Dr. Rashmi believes that with the right knowledge and a healthy lifestyle we can combat many health issues and she strives to spread the same through her blog posts.
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