Does Fasting Increase Testosterone?

Does Fasting Increase Testosterone?

Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.


Fasting has long been a practice associated with spiritual traditions and modern research that confirms its physical health benefits.

Reducing caloric intake through fasting has been shown to support weight loss, balance hormones and improve immune system health - among many other advantages.

Intermittent fasting has many positive effects on insulin and sex hormone-binding globulin (SHBG) levels among pre-menopausal women that regulate various systems in the body, but the few studies available show that it decreases testosterone levels in males.  

What is fasting?

Fasting is the practice of abstaining from food and drink for a certain period of time. There are many different types of fasting, including intermittent fasting, water fasting, and juice fasting.

Intermittent fasting is perhaps the most popular form of fasting, which involves eating during a specific window of time each day, such as an 8-hour period, and fasting for the remaining 16 hours.

Diet and exercise trends often stem from valid scientific evidence; however, once they gain mainstream popularity they often exaggerate benefits and put marketing ahead of scientific evidence.

Intermittent fasting is an example; proponents assert that forgoing meals for several days each week can help people lose weight, reduce chronic disease risks and even extend lifespan.

Intermittent fasting research has yielded promising results in animals, particularly fat rats that exhibit greater weight loss when given shorter intervals between meals and fasting periods.

But studies involving humans are either small or inconclusive and vary greatly in terms of results.

Prior to beginning any diet change, it's wise to seek advice from your physician.

They may suggest starting with a low-calorie diet before slowly adding intermittent fasting. Be sure to drink lots of water (around two or three liters) while fasting.

As an athlete, it's advisable to speak with a registered dietitian regarding the potential advantages and drawbacks of intermittent fasting, particularly before engaging in endurance exercise while fasting.

You don't want to go too long without eating without replenishing muscle mass along with fat stores and glycogen.

Understanding testosterone

Testosterone is a hormone that is produced by the testicles in men and the ovaries in women. It plays a critical role in the development of male characteristics, such as muscle mass, body hair, and a deep voice.

However, testosterone is also important for women's health, as it helps regulate the menstrual cycle and maintain bone density.

Testosterone levels naturally decline as men age, which can lead to a variety of symptoms, such as decreased muscle mass, increased body fat, and decreased libido.

Low testosterone levels can also contribute to depression, fatigue, and a decreased sense of well-being.

The link between fasting and testosterone

One of the most intriguing claims about fasting is that it can boost testosterone levels.

While there is some evidence to support this claim, the research is still in its early stages, and much more needs to be done to fully understand the link between fasting and testosterone.

One study published in the Journal of Clinical Endocrinology and Metabolism found that men who fasted for 24 hours experienced a 67% increase in testosterone levels.

However, the study also found that testosterone levels returned to normal after the fast was over, suggesting that the effects of fasting on testosterone may be temporary.

Another study published in the Journal of Translational Medicine found that intermittent fasting increased testosterone levels in rats.

However, it's important to note that animal studies may not always translate to humans, and more research is needed to determine whether the same effects occur in humans.

As for now, a review of the available research demonstrates that, on the whole,  testosterone levels drop in men. 

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Benefits of fasting

While the research on fasting and testosterone is still in its early stages, there are some potential benefits to incorporating fasting into your diet. One of the primary benefits is weight loss, which can improve testosterone levels in overweight men.

Another potential benefit is improved insulin sensitivity. Insulin resistance is a common condition that can lead to high blood sugar and decreased testosterone levels. Fasting has been shown to improve insulin sensitivity, which could in turn improve testosterone levels.

Finally, fasting has been shown to reduce inflammation, which is a major contributor to a variety of health problems, including low testosterone levels. By reducing inflammation, fasting could help improve testosterone levels and other aspects of health.

Therefore, while it appears there isn't a solid direct link between fasting and increasing testosterone, there could be a long term positive benefit.

Does fasting increase growth hormone?

Research suggests that intermittent fasting increases human growth hormone (HGH). HGH sends signals down from HGH releases directly into either an ovary (for women) or testis (in men), encouraging production of more testosterone.

A 2014 study explains that calorie restriction also encourages the release of an adipocyte-derived hormone called adiponectin, which regulates metabolism and decreases insulin resistance

How to implement fasting

If you're interested in using fasting to help lose weight, there are a few strategies you can use. The first is to start with intermittent fasting, which involves eating during a specific window of time each day, such as an 8-hour period, and fasting for the remaining 16 hours.

You can also try longer fasts, such as 24-hour fasts, once or twice a week. It's important to listen to your body and make sure you're not pushing yourself too hard.

Finally, it's important to focus on a healthy diet when you're not fasting. Eating a diet rich in protein, healthy fats, and complex carbohydrates can help support healthy testosterone levels.

Risks and precautions of fasting 

One of the biggest risks of fasting is dehydration, which can lead to a variety of health problems, including electrolyte imbalances and kidney damage.

It's also important to make sure you're getting enough nutrients when you're not fasting. 

Finally, it's important to listen to your body and make sure you're not pushing yourself too hard.

If you feel dizzy, lightheaded, or nauseous during a fast, it's important to stop and seek medical attention if necessary.

Additional strategies for boosting testosterone levels

One of the most important strategies to improve hormonal balance is to exercise, particularly strength training. Strength training has been shown to improve testosterone levels in both men and women.

Getting enough sleep is also important for healthy testosterone levels. Lack of sleep can lead to increased stress and inflammation. 


Does Fasting Increase Testosterone?

Testosterone production process starts in the brain.

From there, signals from hypothalamus and pituitary gland are sent out to both women's ovaries (in women) and men's testes (in men), telling them to produce this vital hormone that plays such an integral part of both reproductive health and muscle building.

A lack of testosterone may result in low libido, depression or mood swings as well as poor physical performance at gym.

One way to increase testosterone levels is through decreasing chronic inflammation.

This may be caused by excess body fat, stress and medications prescribed for conditions like diabetes - factors which impede production of healthy testosterone levels by the body.

Intermittent fasting has proven an effective method to alleviate such inflammation by blocking pro-inflammatory cytokines and decreasing cortisol levels - both essential for optimal testosterone production levels.

Calorie restriction also helps improve insulin sensitivity and LH hormone health, both essential components for testosterone production.

Insulin helps regulate blood sugar, and having good insulin sensitivity allows your body to use glucose efficiently as energy, while supporting an ideal ratio between Leptin and Adiponectin hormones - essential components in fat burning!

Therefore, while there isn't an abundance of evidence suggesting that fasting will increase your testosterone levels, there could be some secondary benefit from weight loss and a reduciton of inflammation.

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