Does Intermittent Fasting Affect Testosterone Levels?

James Cunningham, BSc, CPT
Published by James Cunningham, BSc, CPT | Staff Writer & Senior Coach
Last updated: April 2, 2024
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As a fitness instructor, I've experimented with various fasting methods to maintain and increase testosterone levels.

Intermittent fasting is known for its health benefits, particularly how it affects hormones through energy restriction.

So, keep reading because I'll review how intermittent fasting can help you deal with low T levels.

Quick Summary

  • Fasting affects testosterone levels by eliminating the excess estrogen, which automatically produces more testosterone hormones.
  • Testosterone levels rise during fasting because of the calorie restriction on different hormones.
  • Short-term fasting can increase testosterone by nearly 180% and luteinizing hormone, which stimulates testosterone production, by up to 67%.
  • In my opinion, combining intermittent fasting with a balanced diet and regular exercise could be a natural way to enhance testosterone levels.

How Does Intermittent Fasting Affect Testosterone Production?

man holding up a plate and thinking

Intermittent fasting boosts testosterone by reducing excess estrogen during autophagy. The natural process of replacing old cells with new ones increases during energy restriction.

Since estrogen opposes testosterone, the more estrogen compounds you produce, the lower your testosterone [1]. Removing excess estrogen may allow the levels of testosterone to rise.

Why Does Testosterone Rise During Intermittent Fasting?

shirtless man showing off his arm muscles

Testosterone increases during fasting due to calorie restriction's effect on hormones like Insulin and LH.

Fasting Improves Insulin Levels

Research in Clinical Diabetes and Endocrinology reveals intermittent fasting boosts insulin sensitivity, reducing resistance [2]. This impacts how the body uses insulin, a crucial hormone from the pancreas. Eating less improves insulin function, aiding glucose balance and weight loss.

Also, it increases insulin production, which limits SHBG [3]. SHBG controls testosterone use in tissues. Enhancing insulin sensitivity through fasting and calorie cuts benefits overall health, including better testosterone regulation.

However, always consult a healthcare expert before making dietary changes that affect your testosterone levels.

Fasting Increases Luteinizing Hormone

ab view of a man with measuring tape

Fasting boosts Luteinizing Hormone (LH), essential for effective testosterone production.

In 1989, a short-term study found that intermittent fasting in men increases LH by up to 78 percent. The study investigated the effect of starvation on the LH levels of nine obese men and eight non-obese men.

According to the National Library of Medicine, while no substantial effect was reported in obese men, fasting increased LH by 67 percent in non-obese men, increasing the overall testosterone boost by 180 percent [4].

This study supports the concept that fasting increases LH hormone health, required for a healthy average testosterone level.

Fasting Increases Growth Hormone

Intermittent fasting naturally increases growth hormones. The human growth hormone (HGH) affects different physiological processes, including immune response, metabolism, and cell growth.

In one study, the increase in HGH after short-term fasting of two days was 400 percent on average. Another showed that growth hormone increases after short periods of starvation.

Although some athletes inject HGH artificially, evidence suggests calorie restriction may be safe to increase this hormone.

HGH works like a gonadotropin, stimulating testosterone through pituitary-testicular functions resulting in testosterone secretions.

Fasting Regulates Leptin, Adiponectin, And Ghrelin Levels

old man with bowl of fruits

Intermittent fasting also affects the levels of other hormones that help you maintain energy levels and store fat.

Intermittent fasting helps regulate Leptin

Your adipocytes primarily produce the "satiety hormone" Leptin. It helps regulate energy balance by signaling to your brain that you are full.

Research suggests that calorie restriction can help reduce excessive production of Leptin, thus improving its sensitivity [5].

Good levels of Leptin and sensitivity effectively regulate metabolic homeostasis by curbing your appetite, increasing energy expenditure, and fat oxidation resulting in weight loss and a rise in your testosterone.

Intermittent fasting helps regulate Ghrelin

Ghrelin is the "hunger hormone," which alerts your hypothalamus that you are hungry. Evidence suggests that intermittent fasting elevates Ghrelin levels, which reduces appetite and food intake.

When you consume fewer calories than you burn, you can lose excess fats. Research suggests that having a leaner body composition also contributes to the increased levels of testosterone [6].

Intermittent fasting helps regulate Adiponectin. 

Adiponectin is another adipose-derived hormone that influences various metabolic processes such as glucose regulation and fatty acid oxidation, which help treat obesity.

Also, when you increase Adiponectin, it results in an increased insulin sensitivity [7] which serves as an indirect avenue that raises significant levels of testosterone [8].

Fasting Helps Lose Body Fat

man showing his belly fat

Research points out that the more body fat you have, the less testosterone your body can produce. Calorie and time-restricted eating can help you gradually drop body fat and create a positive cycle for T production.

According to a 2014 study, calorie restriction could cause an 8 percent weight loss over 24 weeks [9]. For a year, intermittent fasting should allow you to lose 14 percent of your fats.

"There's no denying that anytime you cut calories from your diet, you're going to see the scale drop."

- Despina Hyde Gandhi, RD, CDE, Dietician at NYU Langone's Weight Management Program & President of the Greater NY Dietetic Association

Testosterone is strongly linked to body fat through shared genes. According to research, testosterone has a 23 percent genetic correlation with body fat. That's why decreasing body fat may lower the T levels [10].

person using a tape measure on his body

Hormone resistance and an unhealthy diet may negatively impact testosterone levels [11]. On the other hand, Sclhealth mentions that fasting helps balance your hormones and curbs your appetite [12].

Evidence suggests that men experience a significant decrease in the male hormone testosterone after glucose intake [13].

So there's a big possibility that overeating before a blood test could lead to a false diagnosis of low testosterone levels or hypogonadism.

It may be beneficial to monitor your blood glucose levels to avoid eating before retesting your total testosterone levels.

Studies suggest that energy restriction affects hormones, including Leptin, Ghrelin, Adiponectin, and Growth hormone [14,15]. Also, it can improve insulin resistance and sensitivity, increase LH hormone health, and may contribute significantly to improving low testosterone levels.

"When intermittent fasting is practiced correctly and combined with a low-calorie diet and physical exercise, it significantly lowers your calorie intake and makes it easier to lose weight as you stimulate muscle growth through regular fitness training, which may help to increase your testosterone levels."

- Dr. Branden Staller, MD

What Is Intermittent Fasting?

grey plate and utensils

Intermittent fasting alternates between calorie restriction and regular eating periods. Also known as intermittent energy restriction, its methods vary in intensity and frequency which includes:

  • The 5/2 fast consists of two days per week of restricted calorie intake ranging from 500-600 calories per day, with the remaining five days following a regular meal diet.
  • The 16/8 fast limits how much time you can eat in a day to eight hours. People on this plan usually fast between dinner and lunch the next day.
  • The 24-hour fast entails deciding on one or two days per week when no foods are consumed in the period between two dinners.

Studies indicate that this calorie and time-restricted eating practice is powerful in helping people drop body fat, decrease cancer risk, and improve cognitive abilities [16]. However, further investigation is required to support these findings.

What Are The Benefits Of Intermittent Fasting?

shirtless man giving a thumbs up

According to research, intermittent fasting benefits overall health because it offers several health benefits [17].

Cutting calories can help control blood sugar and may reduce Type 2 diabetes risk. A study revealed that fasting diabetics needed less insulin treatment. It's also good for your heart, lowering blood pressure and boosting good cholesterol.

Calorie restriction might even cut cancer risk by easing oxidative stress and slowing cell aging.

Plus, it perks up mental health in healthy guys, fighting fatigue and low libido, sharpening the mind, and making the brain tougher against injury and illness.

FAQ

Can Intermittent Fasting Benefit Athletes in Terms of Testosterone Levels?

Yes, intermittent fasting can benefit athletes regarding testosterone levels because it enhances hormonal balance and improves insulin sensitivity, which is crucial for maintaining optimal testosterone levels and muscle recovery.

How Does Fasting Impact Hormone Balance in the Body?

Fasting impacts hormone balance in the body by promoting the regulation of key hormones like insulin, leptin, and ghrelin, which play crucial roles in metabolism and overall health.


References:

  1. https://www.health.harvard.edu/blog
  2. https://clindiabetesendo.biomedcentral.com/articles/10.1186/s40842-020-00116-1
  3. https://pubmed.ncbi.nlm.nih.gov/7962291/#:~:text=As%20SHBG%20is%20not%20known,controls%20SHBG%20synthesis%20in%20vivo.
  4. https://pubmed.ncbi.nlm.nih.gov/2686332/
  5. https://pubmed.ncbi.nlm.nih.gov/8784108/
  6. https://blog.insidetracker.com/the-lean-machine-how-your-body-fat-affects-your-health-and-biochemistry
  7. https://pubmed.ncbi.nlm.nih.gov/15655035/
  8. https://diabetesjournals.org/care/article/28/7/1636/27987/Relationship-Between-Testosterone-Levels-Insulin
  9. https://pubmed.ncbi.nlm.nih.gov/21410865/
  10. https://www.sciencedaily.com/releases/2008/08/080805075620.htm
  11. https://academic.oup.com/jcem/article/90/5/2636/2836773?login=false
  12. https://intermountainhealthcare.org/blogs/does-intermittent-fasting-actually-work
  13. https://www.diabetes.co.uk/news/2016/sep/men-experience-an-abrupt-decrease-in-testosterone-levels-after-sugar-intake,-study-finds-99746064.html#:~:text=register%20freestyle%20libre-,Men%20experience%20an%20abrupt%20decrease%20in,after%20sugar%20intake%2C%20study%20finds&text=Researchers%20from%20Massachusetts%20General%20Hospital,in%20the%20male%20hormone%20testosterone.
  14. https://www.healthline.com/nutrition/10-health-benefits-of-intermittent-fasting#:~:text=Many%20of%20the%20benefits%20of,of%20cells%2C%20and%20gene%20expression.&text=When%20you%20fast%2C%20insulin%20levels,change%20which%20genes%20they%20express.
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4027830/
  16. https://www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156
  17. https://www.bouldermedicalcenter.com/intermittent-fasting-and-health/
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About The Author

James Cunningham, BSc, CPT
Staff Writer & Senior Coach
James Cunningham, BSc, CPT holds a BSc degree in Sport & Exercise Science from University of Hertfordshire. He's a Health & Performance Coach from London that brings a unique blend of academic knowledge of health supplements and practical exercise experience to the table for his readers.
Learn more about our editorial policy
Dr. Kristy June Dayanan, BS, MD is an author with a BS degree from University of the Philippines and an MD from University of Perpetual Help System. Her ability to simplify medical science complexities and dietary supplement jargon for the average reader makes her a valued medical fact checker and reviewer.
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Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
Learn more about our editorial policy

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