Killing Your Sex Drive One Bite at a Time

5 Surprising Ways Sugar Lowers Libido

Our hormones don’t operate in a vacuum. They are interconnected, performing like a big musical symphony. When one becomes out of balance, others are sure to follow.  Sex hormones, healthy blood sugar, and insulin balance are more intimately linked than you might think. Spikes in insulin, and the insulin resistance that results from eating too much sugar and flour, can lead to acne and irregular menstrual cycles and can make women lose hair where they want it and grow hair where they don’t. Men with blood sugar imbalances have trouble getting or maintaining erections and often get “man boobs.”

We’ve somehow thought these and other symptoms become normal as we age. They don’t. Libido-crashing mood disorders in women and men reaching for a “little blue pill” do not need to be a part of the aging process.  Bad habits such as drinking and smoking, exposure to environmental toxins, and being chronically stressed all diminish sex hormone balance.  Yet, the biggest culprit that continually knocks sex hormones out of balance is sugar in all its many forms (including all flour products), which raises insulin and creates a hormonal domino effect. Once you understand how insulin can impact other hormones, you begin to connect the dots about how excessive sugar can wreck your sex life.

1. Sugar lowers testosterone.

In men, insulin resistance brought on by excessive amounts of sugar drives down testosterone, the hormone responsible for numerous functions including sexual well-being.

Sex drive and sexual function take a big hit. Decreased muscle mass and more belly fat are also repercussions of low testosterone in men. That excess body fat can increase levels of the hormone estrogen, leading to low sex drive and trouble getting erections.

In a study published in Clinical Endocrinology, where 74 men of varying ages underwent an oral glucose tolerance test, researchers found glucose (sugar) induces a significant reduction in total and free testosterone (T) levels.  Testosterone isn’t just a guy’s hormone. Imbalanced levels of this hormone in women can reduce desire, increase body fat, lower muscle mass, and create a fuzzy memory.

2. Sugar creates leptin resistance.

Leptin puts the brake on your appetite. This hormone tells your brain to stop eating.

When you eat a lot of sugar, processed foods, and flour, leptin doesn’t work anymore. Fat cells continue to produce leptin, but your brain doesn’t “hear” its call and eventually becomes leptin resistant. I often see insulin resistance and leptin resistance go hand in hand with my patients.

Leptin also monitors sexual behavior. One study in the journal Clinical Endocrinology looked at three groups of men and found those with higher leptin levels—most likely due to leptin resistance—also had significantly higher body mass index (BMI) and lower levels of testosterone.

So, now you have insulin resistance, leptin resistance, and lower testosterone. Can you begin to see how this spells trouble for your sex drive?

3. Sugar reduces growth hormone (GH) production.

Growth hormone (GH) is your “fountain of youth” hormone that you mostly produce during deep sleep. Secreted by the pituitary gland, GH improves muscle mass, helps your body utilize fat, and helps maintain optimal libido.  Reduced muscle mass, increased abdominal obesity and risk for Type 2 diabetes, and lower libido are hallmark symptoms of GH deficiencies.

Researchers find a direct link between GH, insulin levels, and sexual function. Studies show insulin reduces your body’s ability to make growth hormone (GH), altering testosterone levels and reducing libido.

4. Sugar makes you tired.

Sugar and other high-glycemic carbohydrates will increase your blood sugar, leading insulin to pull it back down. Insulin usually over-compensates, pulling your blood sugar down too low and leading to hunger, cravings, and fatigue. That’s one way to explain how that big bowl of pasta knocks you out of the mood.  Sugar makes you tired in other ways, too. Orexin is a neurotransmitter that regulates eating behaviors, wakefulness, and arousal.  A study published in the journal Neuron found amino acids (protein) increase orexin neurons and boosted alertness. Excessive sugar, on the other hand, decreased orexin, contributing to fatigue and drowsiness.

5. Sugar triggers stress and anxiety.

Excessive amounts of sugar have an interesting effect on the body, simultaneously leaving you tired but also wired. Why is it that you eat a big piece of chocolate cake and feel full, yet an hour later, you crave another piece, even though you know it makes you feel crummy?  That’s the feeling of your blood sugar crashing, leading to hunger, cravings, brain fog, and a definite not-in-the-mood feeling. Those blood sugar imbalances often trigger mood swings, depression, and anxiety.  High insulin levels also exacerbate chronically elevated levels of cortisol, your stress hormone. When the two hormones stay elevated long after they should taper down, they perform as a team to break down muscle mass, store fat, and dampen libido. Overall, it’s not a pretty picture. 

Rebalancing Your Sex Hormones

If you suspect sex hormone imbalances, ask your doctor to test them. Males should test total and free testosterone. Females should test follicle stimulating hormone (FSH), luteinizing hormone (LH), Dehydroepiandrosterone sulfate (DHEA-S), estradiol, progesterone, free testosterone, and sex hormone binding globulin.

Rebalancing these hormones could be as simple as what you put on your fork. Food is information that controls your gene expression, hormones, and metabolism. Choose low-glycemic, real foods, including fresh vegetables, fruits, legumes, non-gluten grains, nuts, seeds, and high-quality animal protein.

by Mark Hyman, MD