Do Low-carb Diets Lower Testosterone Levels?

Testosterone is an essential hormone for men, influencing various aspects of their health and well-being. It is not only vital for sexual function and reproduction but also plays a crucial role in bone strength, muscle development, mood regulation, and the prevention of chronic diseases such as obesity, diabetes, and cardiovascular conditions. Thus, maintaining adequate testosterone levels is crucial for men to sustain optimal health and vitality. However, it is important to note that certain dietary choices can negatively impact testosterone production in men.

A low-fat diet reduces testosterone

Recent research suggests that low-fat diets can have a negative impact on testosterone levels in men. A systematic review and meta-analysis study published this year analyzed data from six high-quality studies involving 206 participants. The results showed that men who followed a low-fat diet experienced an average decrease of 10% to 15% in testosterone levels compared to those on a high-fat diet.

This effect was particularly significant for individuals following a vegetarian, low-fat diet, which led to a reduction of up to 26% in testosterone levels. Although further randomized controlled trials are required to confirm these findings, the current high-quality data indicates that low-fat diets, especially low-fat vegetarian diets, may indeed lower testosterone levels in men.

Consuming adequate quantities of high-quality fats is crucial for testosterone production. High-quality fats help maintain healthy cholesterol levels, which serve as a precursor and essential building blocks for testosterone synthesis. Furthermore, natural food sources rich in high-quality fats and cholesterol also provide other important nutrients, contributing to both testosterone synthesis and overall health.

Pro-inflammatory foods reduce testosterone

In addition to low-fat diets, the consumption of pro-inflammatory foods is another significant factor in reducing testosterone levels in men. A recent study utilized data from the National Health and Nutrition Examination Survey (NHANES), focusing on men aged 20 or older who had provided dietary intake history and underwent serum sex hormone testing.

To ensure the study’s reliability, the researchers employed weighted ratio and multivariate analysis methods, controlling for factors such as age, race, physical fitness, smoking, education level, body mass index, and venipuncture time.

The findings of the study revealed that men who consumed excessive amounts of pro-inflammatory foods were approximately 30 percent more likely to experience testosterone deficiency. Specifically, obese men who followed a pro-inflammatory diet had a 60 percent higher likelihood of testosterone deficiency.

But what exactly are considered “pro-inflammatory foods”?

Studies have identified foods rich in undesirable components, such as refined carbohydrates and refined seed oils, as common contributors to inflammation. These types of foods can be classified as pro-inflammatory.

Furthermore, a study mentioned earlier highlighted the damaging effect of omega-6 polyunsaturated fatty acids, mainly found in refined seed oils. These fatty acids are highly unstable and prone to oxidation, which can lead to damage to germ cells and impede testosterone production.

Refined carbohydrates reduce testosterone

Eating excessive amounts of refined carbohydrates, such as sugar, noodles, rice, and refined seed oils, can contribute to insulin resistance, which has detrimental effects on testosterone levels in men.

Insulin is responsible for lowering blood sugar and promoting muscle tissue growth. However, prolonged high levels of insulin caused by overconsumption of refined carbohydrates and other foods can lead to insulin resistance. In this condition, cells become less responsive to insulin, leading to various health risks, including lower testosterone levels in men.

Research indicates that insulin resistance increases the likelihood of sexual dysfunction in men, with more severe insulin resistance correlating with more significant sexual dysfunction.

One way to measure insulin resistance is through indicators related to “metabolic syndrome” (also known as “insulin resistance syndrome”). If a person meets three out of five indicators, it indicates the presence of insulin resistance, and the more indicators met, the more severe the insulin resistance.

A study conducted in Italy involving 800 patients with sexual dysfunction revealed that as the number of metabolic syndrome markers increased (indicative of more severe insulin resistance), levels of the male hormone testosterone decreased. Patients with three metabolic syndrome indicators had more than a threefold increase in the prevalence of hypogonadism. When all five indicators were exceeded, the prevalence increased by tenfold.

Several mechanisms contribute to this association. Firstly, human adipose tissue contains an enzyme called aromatase, which converts testosterone to estrogen. Insulin resistance promotes obesity, increases adipose tissue content, and reduces testosterone levels in men.

Secondly, to achieve an erection, a man requires adequate blood flow to the penis. Insulin resistance damages blood vessels, and fat tissue releases pro-inflammatory factors that further impair blood vessel function, resulting in reduced blood flow to the penis.

Thirdly, studies have shown that insulin directly suppresses testosterone production, indicating that higher insulin levels correspond to lower testosterone levels in men.

Finally, insulin resistance can cause nerve damage, making it more difficult for men to maintain an erection and experience pleasure.

Given these implications, insulin resistance can be considered a “sex killer” for men. It is essential to reduce the consumption of refined carbohydrates and refined seed oils that can contribute to insulin resistance.

Evidence reveals a significant decline in male testosterone levels, with up to 20% to 50% of men experiencing insufficient testosterone. This decline has been particularly pronounced since the mid-20th century, coinciding with drastic shifts in dietary habits.

What specific dietary changes have occurred?

One notable change is the introduction of official dietary guidelines in the United States, beginning in 1980, which advised reduced meat and saturated fat consumption while advocating for increased intake of carbohydrates and fats, predominantly vegetable oils, without stringent restrictions on sugars.

This dietary shift has led to three major changes in people’s eating habits:

• Reduced consumption of meat and high-quality fats.
• Widespread use of refined seed oils.
• The increased popularity of sugar and refined carbohydrate-rich foods.

To maintain adequate testosterone levels, it is crucial for men to focus on three dietary aspects:

• Avoid low-fat diets and ensure sufficient intake of meat and high-quality fats.
• Steering clear of pro-inflammatory diets and minimizing consumption of inflammatory foods such as refined seed oils.
• Not consuming diets high in refined carbohydrates. Foods like sugar, noodles, and rice are known to contribute to insulin resistance, which can negatively impact testosterone levels.

Low testosterone levels can lead to various problems in men, including hypogonadism, which can result in erectile dysfunction, lower sperm quality, and male infertility. Additionally, low testosterone levels can contribute to osteoporosis, muscle weakness, fatigue, and mood disorders. Men with low testosterone are also at a higher risk of chronic metabolic diseases such as obesity, diabetes, and cardiovascular disease. Therefore, maintaining adequate testosterone levels is crucial for overall male health.

Scientific low-carb diet

When it comes to increasing testosterone levels, following a properly executed ketogenic, low-carbohydrate diet that includes sufficient meat and high-quality fats, reduces the consumption of pro-inflammatory foods like refined seed oils, and limits or eliminates refined carbohydrates like sugar, noodles, and rice, can be beneficial.

Scientific research supports the effectiveness of this dietary approach. A study published in the journal “Nutrients” in 2020 found that a very low-calorie ketogenic diet improved testosterone levels, gonadal function, and prostate health indicators in obese men after approximately 13 weeks. This suggests that a very low-calorie ketogenic diet can serve as a noninvasive and efficient treatment for metabolic hypogonadism and lower urinary tract symptoms in obese patients.

It’s important to note that the aforementioned study used a very low-calorie ketogenic diet, which is different from the daily unrestricted calorie ketogenic diet commonly followed by individuals. However, another study published in the journal “Clinical Nutrition” this year investigated the effects of a ketogenic, low-carbohydrate diet alongside strength training. The study involved two groups, one following a very low-carbohydrate ketogenic diet and the other following a moderately low-carbohydrate, high-fat, and high-cholesterol diet. After an 8-week trial period, both groups experienced a significant increase in basal testosterone and free testosterone levels.

While one might wonder if the increase in testosterone is solely due to ketone production or low-carbohydrate intake, a reference study from 2017 helps shed light on this matter. The study involved 25 fitness experts divided into two groups, with one following a ketogenic diet and the other consuming a high-carbohydrate diet. Both groups had the same calorie and protein ratios in their diets. After 11 weeks, both groups demonstrated similar improvements in muscle size, absolute strength, and explosive power. However, the ketogenic diet group showed greater fat loss and a significant increase in serum testosterone levels compared to the high-carbohydrate diet group.

These findings suggest that following a ketogenic, low-carbohydrate diet, in combination with strength training, can lead to a significant increase in testosterone levels. It indicates that the ketogenic diet itself, rather than just strength training, plays a role in the observed testosterone increase.

Daily diet reference：

Daily diet reference for men with low physical activity and a goal of appropriate calorie intake (below 1200 kcal):

• Breakfast: 2 slices of whole wheat bread (150 kcal) + 2 boiled eggs (150 kcal)
• Lunch: Mixed green salad with grilled chicken breast (200 kcal) + steamed vegetables (150 kcal)
• Dinner: Grilled salmon fillet (250 kcal) + roasted Brussels sprouts (100 kcal) + cauliflower rice (100 kcal)

For individuals aiming to lose weight or stabilize blood sugar levels, it may be beneficial to lower carbohydrate intake while maintaining adequate protein and healthy fat consumption. By reducing the portion sizes of rice or replacing it with low-carbohydrate alternatives like cauliflower rice, individuals can modify the above meal plan to suit their goals and dietary needs.