Extreme Dieting Hurts your Endorine System

We’ve heard of the “starving artist,” the “all-too-skinny model”, and the “skin-and-bones corporate worker.” But, why does everyone have to go hungry? Yes, food in the United States SUCKS. But, that doesn’t mean you’re out of options. The idea that we must fit into body conventions seen in media is extremely outdated. It’s important to remain healthy, but arbitrarily going on diets does more harm than good.

Extreme dieting, whether it’s excessive calorie restriction, extreme low-carb or low-fat diets, or long-term fasting, is increasingly popular as a way to lose weight quickly. However, these practices can disrupt the delicate balance of your endocrine system, which controls the body’s hormones and regulates nearly every physiological function. When hormonal balance is disturbed, the consequences are wide-ranging, affecting everything from metabolism and mood to reproductive health and immune function.

a. Calorie Restriction and Metabolic Hormones

Drastically cutting calories lowers leptin (fullness hormone produced by your endocrine system) and raises ghrelin (hunger hormone), leading to increased cravings and binge eating. It also slows thyroid hormones, which reduces metabolism, and raises cortisol, the stress hormone, contributing to belly fat and adrenal fatigue.

b. Low-Fat Diets and Sex Hormones

Healthy fats are crucial for producing sex hormones like estrogen and testosterone. Low-fat diets can lead to low estrogen levels in women, affecting menstrual cycles and bone health, and lower testosterone in men, leading to reduced muscle mass and energy. For women, low-fat diets can increase the risk of amenorrhea (loss of menstruation).

Men adhering to low-fat diets tend to have lower average testosterone levels compared to those on less restrictive or high-fat diets. For instance, one analysis found that men on low-fat diets had an average serum testosterone level of 410.8 ng/dL, compared to 443.47 ng/dL in those on unrestricted diets. This decrease is statistically significant and suggests that dietary fat plays a role in hormone regulation [4], [5]

Dietary fats, especially saturated and monounsaturated fats, are critical for the synthesis of cholesterol, which serves as a precursor to testosterone. A lack of adequate dietary fat may hinder this process, leading to reduced androgen production which can cause fatigue, anxiety and depression, difficulty concentrating, poor exercise tolerance, low sex drive and erectile dysfunction. [4], [5], [6]

c. Low-Carb Diets, Insulin, and Cortisol

Extremely low-carb diets can disrupt insulin and cortisol. While reducing carbs can benefit blood sugar control for some, too few carbs can destabilize blood sugar levels, spike cortisol, and suppress thyroid hormones, slowing metabolism.

Ever heard of the KETO diet trend? It’s a high-fat diet that is said to boost energy levels by burning fat instead of carbs. What the media doesn’t mention is the Keto Flu, and guess what? It’s not necessarily synonymous with the Keto diet. When any diet is not properly balanced and maintained, they have the opposite of their intended effect— they can weaken your system and decrease energy. When starting a low-carb diet, the body shifts from using glucose as its primary fuel source to burning fat and producing acids called ketones. This adaptation period, often called "keto flu," can lead to fatigue, brain fog, and low energy as glycogen stores are depleted.

Up to 25-30% of people starting low-carb diets report experiencing symptoms of keto flu, which may last 1-2 weeks [7]

d. Fasting and Hormone Health

Long periods of fasting can lower reproductive hormones in women, disrupt the menstrual cycle, and cause adrenal stress. Men may experience decreased testosterone and energy. For some, fasting creates blood sugar imbalances, triggering cortisol spikes that stress the adrenals.

e. Nutrient Deficiencies

Extreme dieting often limits nutrient variety, leading to deficiencies in vitamins and minerals essential for hormone production (like magnesium, zinc, and B vitamins) and fiber, which supports gut health and estrogen balance.

Vitamin D: This vitamin is crucial for hormone regulation, particularly in maintaining thyroid health and supporting sex hormones like testosterone and estrogen. A deficiency is associated with conditions like Hashimoto’s thyroiditis and decreased bone density. Globally, vitamin D deficiency is widespread, affecting up to 1 billion people, particularly in regions with low sun exposure​ [8], [9]

Zinc: Zinc plays a role in hormone synthesis, including testosterone production, and is critical for immune function. Around 17.3% of the global population is at risk of zinc deficiency, with rates higher in some regions, leading to impaired hormonal function and fertility issues​ [8], [9]

Magnesium: This vitamin supports over 300 enzymatic reactions, including those related to hormone regulation. It helps balance cortisol (stress hormone) and supports the production of sex hormones like estrogen, progesterone, and testosterone. It is critical for melatonin production, influencing sleep cycles, which indirectly affects overall hormone health.

Approximately 50% of adults in the U.S. fail to meet the recommended daily magnesium intake, which is 400–420 mg for men and 310–320 mg for women. This deficiency is more common in older adults, people with type 2 diabetes, and those with gastrointestinal diseases​ [10], [11] Magnesium deficiency is linked to increased cortisol levels, fatigue, and reduced testosterone in men, potentially affecting sexual and reproductive health​

[12].

B vitamins: Particularly B6, B9 (folate), and B12, are essential for the synthesis of neurotransmitters and steroid hormones. Vitamin B6 regulates mood-related hormones like serotonin and dopamine. It also helps manage estrogen and progesterone balance, which is particularly important for menstrual and reproductive health. Vitamin B12 deficiency affects 6-15% of the global population, with higher rates among the elderly and vegetarians​. [10] Deficiency in B6 can impair the production of neurotransmitters and lead to hormonal imbalances that affect mood, energy levels, and menstrual cycles​. [11] A deficiency in B12 and folate is linked to elevated levels of homocysteine, which can affect cardiovascular health and disrupt hormonal regulation​. [12]

Long-Term Effects and Restoring Balance

Extreme diets can lead to issues like decreased bone density, mood changes, and metabolic damage. Instead, opt for balanced diets with enough calories, healthy fats, fiber, and varied nutrients to support hormone health. Sustainable dietary practices ensure both weight management and optimal hormone function. Don’t take your nutritionist for granted!

Adopting a balanced, nutrient-rich diet and avoiding extreme restrictions provides a healthier, long-term approach to supporting the endocrine system and overall well-being.

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