A question people ask a lot is how diet affects testosterone. What you’ll find if you delve into the research is that the relationship between diet and testosterone is inherently complicated.
For example, the macronutrients have different effects on testosterone acutely versus over the long term. In one study, when men with normal testosterone levels drank a carbohydrate beverage that contained glucose, they had an acute drop in testosterone that lasted for two hours. Researchers concluded that refined carbs, which trigger a large blood sugar spike, are bad for testosterone levels.
But, we also know that over the long-term, carb intake can support testosterone release. Very low-carb diets lead to reductions in testosterone, which is one reason that getting carbs from whole, complex sources is generally recommended.
It’s enough to leave anyone confused. Therefore, this article will give you research-based facts about the interplay between nutrition, hormones, and body composition.
Fact #1: Frequent blood sugar spikes reduce testosterone.
All carbs are not created equally. The body responds very differently to complex carbs like vegetables, fruit, or even whole grains than it does to processed carbs like bread or pasta. The fiber in whole, complex carbs leads to slower digestion and more moderate elevation in blood sugar and insulin.
In contrast, refined carbs are very quickly digested by the body, which leads to a quick release of sugar into the blood, spiking insulin. Hormones tend to function in a cascade-like fashion and this elevation in blood sugar and insulin leads to a drop in testosterone.
Avoid sugar and refined carbs that repeatedly spike blood sugar.
Fact #2: Very Low-Carb Diets Reduce Testosterone
Lower carb diets lead to lower testosterone levels. For example, healthy, young men who were put on a higher protein, lower carb diet had lower testosterone but higher cortisol than a group that ate a higher carb, lower protein diet. Calories and fat were equal in the diets.
One reason for the negative effect on hormones is that glucose is necessary for release of gonadotropin-releasing hormone (GnRH), which is a precursor hormone to testosterone. When glucose levels are low, GnRH stimulation of leydig cells is reduced, as is testosterone.
This is likely an evolutionary adaption so that the reproductive system is able to sense changes in energy status to prevent reproduction during times of food scarcity.
For peak testosterone levels, a higher carb intake is necessary. Aim to include healthy carbs in reasonable quantities.
Fact #3: Carb intake affects athletic performance and the testosterone-to-cortisol ratio.
One benefit of a higher carb intake from whole sources is lower cortisol levels, which may enhance recovery and help you avoid overtraining. For example, researchers wanted to test how dietary composition influences the free testosterone-to-cortisol ratio, which is a proposed biomarker for training stress in athletes.
Results showed that when male subjects performed intense workouts three days in a row, those who ate a lower carb diet (30 percent of the diet) had an increase in cortisol and a 43 percent decrease in the testosterone-to-cortisol ratio. A high-carb intake (60 percent of the diet) led to no change in cortisol or the T-to-C ratio.
Higher carb diets are great for peak performance and recovery. If weight management is a goal, be sure to favor whole carbs, plenty of protein and healthy fat. Have carbs later in the day and around workouts.
Fact #4: Adequate fat intake is necessary for testosterone production.
Testosterone and other androgen hormones are produced out of cholesterol, which comes from dietary fat. For instance, studies show that reducing fat intake from 40 to 20 percent of the diet resulted in significantly lower testosterone levels. In addition, vegetarians who have a lower fat intake than omnivores have consistently lower T levels.
If for some reason you need to reduce your fat intake, it’s possible to minimize the drop in T by getting adequate saturated fat in your diet. In studies that replace polyunsaturated fats with saturated fats, testosterone is between 10 and 20 percent higher in the saturated fat condition.
Don’t be afraid of fat. Eat a balanced fat intake from grass-fed animal products, fish, nuts, avocado, olive oil, and coconut oil.
Fact #5: Calorie restriction leads to lower testosterone and muscle loss.
Another factor that greatly affects testosterone is calorie restriction. For example, in one study of normal weight women, those who cut calories to lose 1 kg a week had a 30 percent reduction in T compared to a group that had half the calorie deficit in order to lose 0.5 kg a week.
Similar results are evident in men, showing that when energy availability is low due to dieting, testosterone and other androgens are substantially reduced regardless of fat intake. Muscle mass is often lost, but this is due to a catabolic state, high cortisol, and a lack of calories rather than low T. Using occasional higher calorie/higher carb meals can help to prevent the drop in muscle mass.
Avoid slashing calories. The greater the degree of energy restriction, the greater the loss of muscle mass and reduction in androgen hormones.