Written by Steve Theunissen | ISSA: CPT & Fitness Nutrition
Fact checked by Andrew Lenau, ISSA CPT & Sports Nutritionist
FACT CHECKED
Intermittent fasting has become a popular weight loss strategy, having proven itself as an effective way to strip off body fat. There are all sorts of health-promoting extra benefits that come with fasting, from reducing inflammation to improving brain power. But does intermittent fasting increase testosterone?
Many believe fasting will promote natural testosterone release, while others believe the opposite. So what do the science-supported facts say? Let's take a deep dive to find out, once and for all, whether fasting increases testosterone.
Table Of Contents:
- Can Fasting Increase Testosterone?
- But Can't Weight Loss Help Increase Testosterone Levels?
- What Does Fasting Help?
- What Can Help Raise Testosterone Levels?
- What Are Some Different Types Of Fasting?
- Other Fasting and Testosterone FAQs
Can Fasting Increase Testosterone?
No, fasting will not boost testosterone, though it may indirectly promote weight loss. The belief that testosterone can directly impact testosterone production stems from a 1989 study (1).
This study suggested that intermittent fasting may increase testosterone production by as much as 180%. What is often missed is that the test subjects were given a gonadotropin-releasing hormone injection, which fast-tracks testosterone secretion. Also, the testosterone levels quickly diminished, actually ending up lower than baseline.
More recent studies have consistently shown that fasting decreases testosterone levels. Four studies have been done over the last decade involving healthy young men practicing time-restricted eating and doing a weight training program. Study lengths ranged between 4 and 44 weeks (2).
Researchers believe fasting leads to lower testosterone levels because of how the body responds to calorie restriction. It does so by prioritizing essential functions for survival. As producing new testosterone isn't a survival mechanism, it slows down when we're in that state.
But Can't Weight Loss Help Increase Testosterone Levels?
Yes, weight loss can help increase testosterone levels, and fasting has proven to be an effective method of fat loss. So, fasting may indirectly help with testosterone production by contributing to weight reduction. But it doesn't do so directly.
On the flip side, excess weight gain promotes insulin resistance, which reduces the levels of sex hormone-binding globulin (SHBG), a compound essential for testosterone production (3). So, if you have excess weight, it will decrease testosterone levels. Losing it could give you a testosterone boost by recharging SHBG levels.
What Does Fasting Help?
Historically, fasting was undertaken to combat illness, not to lose weight. Today, that scenario has flipped, so many people are surprised to learn about the health benefits that fasting produces. Here are three key areas of health that fasting helps:
1) Chronic Inflammation
The body clears away damaged cells during fasting periods through a process known as autophagy, helping to reduce inflammation (4). The longer your fast, the more your body can clear away damaged cells, so if you're doing it for this benefit, consider a 3-day fast. Fasting may also lower the levels of such inflammatory markers as interleukin-6 and c-reactive protein.
Finally, fasting can positively affect the microbiome of the gut, encouraging the growth of good bacteria. The more balanced the gut flora is, the lower the likelihood of inflammation.
2) Oxidative Stress
Oxidative stress takes place when antioxidants and free radical molecules are unbalanced. Free radical molecules cause damage to the body's cells. Fasting has been shown to reduce oxidative stress. It does this by stimulating the production of a couple of antioxidants that negate the effects of free radicals, superoxide dismutase (SOD) and catalase (5).
Fasting has been shown to improve the function of mitochondria, which is the cell's energy factory. This may offset the mitochondrial damage, which contributes to oxidative stress.
3) Connection With Luteinizing Hormone
The relationship between luteinizing hormone (LH), a key part of the reproductive process, and intermittent fasting is the subject of ongoing study.
Fasting may assist in regulating the signaling pathways and synthesis of hormones, which may indirectly affect the equilibrium between LH and other hormonal processes in the body (6). Fasting has the potential to make the body more sensitive to hormones, which would boost the efficiency of hormonal processes, especially those involving LH.
What Can Help Raise Testosterone Levels?
Increasing testosterone levels naturally comes down to adopting healthy lifestyle choices and making smart nutritional choices. Here are the four key areas you need to be on top of:
1) Exercise
Weightlifting and other forms of resistance exercise promote muscular growth. Greater testosterone synthesis can result from greater muscle mass because muscles produce myokines, signaling molecules that can affect hormone production. Exercise can help with weight loss, especially visceral fat, which is linked to more significant amounts of estrogen and lower testosterone levels.
Testosterone and human growth hormone levels can increase by losing extra fat. Exercise has also been shown to relieve stress, and ongoing stress can lower testosterone levels. Working out can promote endorphin release and lower cortisol, so here are 5 Exercises That Increase Testosterone to add to your workouts.
2) Quality Sleep
Getting enough good sleep is essential for hormone balance, particularly the creation of testosterone.
The body creates and releases testosterone during the deepest depths of sleep. Consistently obtaining enough sleep guarantees the body enough time to produce hormones and recover. Deep, restorative sleep is crucial for good sleep quality. Hormone regulation can be affected by poor sleep quality and interrupted sleep cycles.
Aim for 7-9 hours of sound sleep each night.
3) Vitamin D
Vitamin D is needed for the production of several hormones, including testosterone. Making sure you're getting plenty of Vitamin D can, therefore, help with testosterone levels. Sunlight is a primary source of Vitamin D, so the more natural sun exposure you can get, the better.
Read more about vitamin D's importance to T levels in our article: Does Vitamin D Boost Testosterone?
4) Diet
A diet high in healthy fats and protein and low in processed carbs is best to promote testosterone production.
Include such fats as avocados, fatty fish, and almonds as they provide the fatty acids needed for hormone production. Protein helps with muscle growth, which indirectly increases testosterone levels. Get your protein from eggs, chicken, fish, red meats, nuts, seeds and legumes. These protein sources also include minerals needed for testosterone production, such as magnesium and zinc.
Limit processed carbs and sugar intake as these contribute to insulin resistance, a suppressor of testosterone.
What Are Some Different Types Of Fasting?
There are many ways to do intermittent fasting. Here are five of the most popular methods:
1) 16/8 Fast
The 16/8 fasting strategy incorporates a daily 16-hour fast and an 8-hour window for eating. This usually entails foregoing breakfast, starting to eat at noon, and completing it by eight o'clock. You only ingest non-caloric beverages, such as water, tea, or coffee without sugar or cream, during the 16-hour fast.
If you want to try out this fast, take a look at The Best 16/8 Intermittent Fasting 7 Day Meal Plan to get you started.
2) Alternate Day
In alternate-day fasting, normal eating days alternate with days when you fast or consume very few calories. On days when they are fasting, people may drastically cut back on their caloric intake or skip meals entirely. They eat as normal on days when they don't fast. Alternate-day fasting can be done in various ways, including modifications that let people eat some calories on their fasting days.
3) 5:2 Method
The 5:2 technique calls for regular eating five days a week and then two non-consecutive "fasting" days with much lower calorie intake (often 500–600 calories). You can choose the fasting days based on your schedule, but they shouldn't fall back on each other. You consume your regular diet on days when you are not fasting.
4) Eat-Stop-Eat
Eat-Stop-Eat is a more extended version of intermittent fasting in which you fast once or twice weekly for 24 hours. For example, you might begin fasting after dinner one day and end it with dinner the next, giving up all calorie-consuming activities for a whole day.
5) Warrior Diet
The Warrior Diet involves a prolonged 20-hour fast followed by a 4-hour feeding window, usually in the evening. Only tiny servings of raw fruits and vegetables and protein-rich foods like lean meats or dairy are permitted throughout the prolonged fasting period. The idea of eating like ancient warriors, who frequently absorbed the majority of their calories in the evening, served as the inspiration for this strategy.
To learn more, read: Everything You Need To Know About 20/4 Fasting.
Other Fasting and Testosterone FAQs
Let's take a look at some of the more common lingering questions about testosterone and fasting.
Does fasting raise testosterone levels?
No fasting does not increase testosterone levels. An early study suggested it could, but several recent studies show the opposite. In fact, these studies suggest that intermittent fasting may actually lower testosterone. When calories are dramatically reduced, the body goes into a starvation response, prioritizing essential functions. As a result, hormone production may be minimized.
What increases testosterone the fastest?
The fastest way to increase testosterone naturally is to follow a regular, intense weight training program. Compound exercises such as squats, deadlifts, and bench presses are especially good at promoting testosterone production.
There are, of course, more direct methods, such as testosterone replacement therapy. If you're interested in going that route, check out our article: Does TRT Help With Weight Loss?
What are the benefits of fasting for men?
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Weight Loss: By lowering calorie consumption and fostering fat loss, fasting can help men reach and maintain a healthy body weight. Alternate day and intermittent fasting are two fasting strategies that can help with weight management.
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Greater Insulin Sensitivity: Fasting may improve insulin sensitivity. The risk of type 2 diabetes can be decreased, and blood glucose levels can be controlled with improved insulin sensitivity.
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Heart Health: According to research, blood pressure, cholesterol, and other heart disease risk factors may all improve with fasting.
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Cognitive Function: For some people, fasting can help with their cognitive abilities and mental clarity. It may increase the production of BDNF, a protein that protects against neurodegenerative illnesses and improves brain function.
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Autophagy: The removal of damaged cells and cellular components by the body occurs during an autophagic process that is triggered by fasting. Cellular healing and longevity are thought to be affected by this mechanism.
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Gut Health: Through the proliferation of beneficial bacteria, fasting may positively affect the gut microbiota.
Does not eating enough lower testosterone?
Yes, not eating enough can reduce testosterone levels.
When the human body doesn't have enough energy (calories) to maintain its essential bodily processes and physical activities, it develops a condition known as low energy availability. A number of detrimental impacts on hormonal health, including low testosterone levels, might result from low-calorie availability. Your body will prioritize the most necessary functions for survival, such as metabolism and organ function. Hormone production is not one of these priorities.
The balance of reproductive hormones can be upset by low-calorie availability, resulting in hormonal imbalances and potential fertility problems. Muscle loss is possible in extreme calorie-restricted settings because the body may break down muscle tissue for fuel. Because of its high metabolic rate, muscle tissue contributes to testosterone synthesis. Therefore, losing muscle mass may also result in decreasing testosterone levels.
Summary Of Fasting And Testosterone
Fasting will not, in itself, promote increased testosterone production. It will, in fact, have the opposite effect. That's because the body responds to starvation when we limit caloric intake. As a result, it prioritizes the key functions needed for survival. These do not include the production of new anabolic hormones, and so testosterone production may diminish slightly.
The best way to naturally encourage testosterone production is to combine resistance training with a healthy diet high in proteins and healthy fats and low in processed carbs. Getting enough Vitamin D through exposure to natural sunlight and through your diet is also important, along with getting 7-9 hours of sleep each night. Use intermittent fasting to strip off body fat and rely on these natural methods to up your 'T' levels.
For a comprehensive look at various fasting techniques and how they can help boost testosterone, check out the 6 Best Intermittent Fasting Methods And Schedules.
References
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Röjdmark S, Asplund A, Rössner S. Pituitary-testicular axis in obese men during short-term fasting. Acta Endocrinol (Copenh). 1989 Nov;121(5):727-32. doi: 10.1530/acta.0.1210727. PMID: 2686332.
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Cienfuegos S, Corapi S, Gabel K, Ezpeleta M, Kalam F, Lin S, Pavlou V, Varady KA. Effect of Intermittent Fasting on Reproductive Hormone Levels in Females and Males: A Review of Human Trials. Nutrients. 2022 Jun 3;14(11):2343. doi: 10.3390/nu14112343. PMID: 35684143; PMCID: PMC9182756.
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Fui MN, Dupuis P, Grossmann M. Lowered testosterone in male obesity: mechanisms, morbidity and management. Asian J Androl. 2014 Mar-Apr;16(2):223-31. doi: 10.4103/1008-682X.122365. PMID: 24407187; PMCID: PMC3955331.
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Jordan, S., Tung, N., Casanova-Acebes, M., Chang, C., Cantoni, C., Zhang, D., Wirtz, T. H., Naik, S., Rose, S. A., Brocker, C. N., Gainullina, A., Hornburg, D., Horng, S., Maier, B. B., Cravedi, P., LeRoith, D., Gonzalez, F. J., Meissner, F., Ochando, J., … Merad, M. (2019). Dietary intake regulates the circulating inflammatory monocyte pool. Cell, 178(5). https://doi.org/10.1016/j.cell.2019.07.050
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Motori, E., Puyal, J., Toni, N., Ghanem, A., Angeloni, C., Malaguti, M., Cantelli-Forti, G., Berninger, B., Conzelmann, K.-K., Götz, M., Winklhofer, K. F., Hrelia, S., & Bergami, M. (2013). Inflammation-induced alteration of astrocyte mitochondrial dynamics requires autophagy for mitochondrial network maintenance. Cell Metabolism, 18(6), 844–859. https://doi.org/10.1016/j.cmet.2013.11.005
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Olson BR, Cartledge T, Sebring N, Defensor R, Nieman L. Short-term fasting affects luteinizing hormone secretory dynamics but not reproductive function in normal-weight sedentary women. J Clin Endocrinol Metab. 1995 Apr;80(4):1187-93. doi: 10.1210/jcem.80.4.7714088. PMID: 7714088.
Steve Theunissen
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