The carnivore diet, an extreme form of dietary restriction, has garnered attention for its potential effects on various aspects of health. It involves consuming primarily animal products, virtually eliminating carbohydrates. While some studies suggest that low-carb diets can lead to weight loss and improvements in metabolic health, their impact on women's hormonal balance and menstrual cycles remains a topic of interest and concern.
How Low-Carb Diets May Affect Women's Hormones
Hormones are regulated by the hypothalamus, pituitary, and adrenal glands. These glands interact in complex ways, forming the hypothalamic-pituitary-adrenal (HPA) axis, which is responsible for regulating stress levels, mood, emotions, digestion, immune system, sex drive, metabolism, and energy levels. The glands are sensitive to factors like calorie intake, stress, and exercise levels. Long-term stress can cause an overproduction of cortisol and norepinephrine, creating an imbalance that increases pressure on the hypothalamus, pituitary, and adrenal glands, potentially leading to HPA axis dysfunction. Symptoms of HPA axis dysfunction include sleep problems, a weakened immune system, and a greater risk of long-term health problems such as cardiovascular disease, stomach ulcers, and mental health conditions.
Eating too few calories can act as a stressor, increasing cortisol production. A low-carb diet increased cortisol levels compared to a moderate-fat, moderate-carb diet. Eating too few carbs or calories and experiencing chronic stress may disrupt the HPA axis, causing hormonal problems.
The Carnivore Diet for Women: An Overview
The carnivore diet for women is a meat-only diet that comes close to zero carbs. Animal-based foods are essential. It is essentially a paleo diet taken a few steps further, and a ketogenic diet taken one or two notches stricter. The focus of a carnivore diet is to obtain all your calories from animal products, by consuming meat, organs and animal proteins, which are naturally nutrient-dense foods, rather than aiming for a zero-carb diet. Carnivore dieters also strive to reduce their consumption of inflammatory foods and cooking methods that may lead to gut inflammation and autoimmune issues.
Foods to Eat on a Carnivore Diet for Women
The diet primarily consists of animal products, including:
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- Grass-fed meat
- Organ meats (beef liver, chicken liver)
- Fatty fish (salmon, mackerel, sardines)
- Fish roe
- Shellfish (mussels, oysters, crabs)
- Dairy products (full-fat dairy, Parmesan cheese, goat cheese, hard cheeses)
- Eggs
- Bone broth
- Bone marrow
- Ground beef
- Chicken meat and shredded chicken
- Poultry meat (duck, turkey)
- Fatty meat and fattier cuts
- Ruminant meat (bison, lamb, beef, goat, elk)
- Pork chops
- Water
Foods to Avoid on a Carnivore Diet for Women
The diet excludes plant-based foods, including:
- Vegetables and fruit
- Grains and gluten
- Legumes
- Nuts and seeds
- Inflammatory foods (vegetable oils, seed oils)
- Processed foods
- Sugar, sweeteners, and artificial sweeteners
- Alcohol
- Beverages other than water (coffee, tea, juices)
Potential Benefits of a Carnivore Diet for Women
There are female-specific health benefits for women who eat a mostly meat-based diet. Many of these are associated with hormone regulation and a high-protein intake.
Hormonal Balance
A carnivore diet involves a high intake of cholesterol. Cholesterol is essential for the formation of the sex hormones estrogen and progesterone, as well as testosterone. Eating mostly carnivore can aid with building hormones, alleviating premenstrual syndrome symptoms (PMS symptoms), and increasing fertility in women. By cutting out plant foods, women also minimize exposure to phytoestrogens in fruits, vegetables, grains, soy, and legumes. Phytoestrogens are plant compounds that mimic estrogen in the body and can have an effect on overall estrogen levels.
Low-carb diets have also been shown to help with polycystic ovarian syndrome (PCOS) by lowering insulin levels and male hormones such as testosterone levels. Drastically cutting carbs as with a carnivore diet can help with PCOS and menstrual cycle imbalances. Consuming high levels of vitamin D and calcium has also been proven to delay the onset of menopause in women. Fatty fish, organ meats, and full-fat dairy intake are all great sources of both. A carnivore diet may also help with thyroid disease, as a low-carb, high-fat diet has been shown to reduce hypothyroidism. A diet rich in zinc has been shown to boost thyroid hormones and meat such as lamb and beef are an abundant source of the mineral.
Weight Management
A carnivore diet has been shown to help women shed excess weight. Eating low-carb, nutrient-rich foods with a high-protein intake, can help keep you feeling full and satiated by affecting your leptin levels. Leptin is a hormone released by our fat cells that regulates our hunger cues as well as metabolism. A high-carb diet can mess with leptin signaling by increasing your appetite, and adding pounds to your waistline. The carnivore diet has been shown to increase leptin levels in the body and improve leptin signaling, which can help reduce excess body fat.
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Blood Sugar Regulation
A 2021 study found immense improvement with diabetic participants at lowering high blood sugar levels after following a carnivore diet for over six months. All diabetic participants in the study came off of injectable medications, 92 percent of type 2 diabetic participants came off insulin supplements, and 84 percent came off oral medications. A total of 98 percent of participants resolved or improved their insulin resistance.
Skin Health
The Harvard study also found 92 percent of participants reported improved or resolved dermatologic conditions after adhering to a carnivore diet for six or more months. Cutting sugar and vegetable oils and increasing intake of zinc, vitamin A, and anti-aging foods such as collagen in bone broth and connective tissues, also come with added skin benefits.
Mental Health Benefits
The Harvard study also found 96 percent of participants experienced improved or completely resolved psychiatric conditions. Mental clarity and focus also increased on a carnivore diet, with 85 percent and 83 percent of participants, respectively, reporting improvements.
Potential Risks of a Carnivore Diet for Women
Any diet that eliminates entire food groups is not without controversy. While the list of purported benefits for women is extensive, some nutrition experts caution to keep a few factors in mind if embarking on extremely low-carb diets and animal-only protein sources.
Processed Meats Can Be High in Sodium
If you are sticking with a meat-based diet, it’s important to remember that not all animal foods are created equal. Red and processed meat intake has been linked to cancer. Try to limit your intake of turkey jerky, pork rinds, and luncheon meats as they are likely to contain high levels of sodium, as well as sugar and other additives. Being a label-sleuth is of utmost importance if buying meat that comes in a package. Ideally, the animal protein should be the only ingredient.
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Essential Nutrients Are Found in Vegetables and Fruit
Essential vitamins and minerals, like vitamin C and potassium, may be lacking on an all-meat diet. You are also at risk of not consuming adequate fiber on a carnivore diet, which can be detrimental to immunity, bowel, and gut health.
Not Suitable For Pregnant or Nursing Women
There are anecdotal reports that following a carnivore diet for women while pregnant or breastfeeding may be too stringent and difficult to maintain appropriate calorie intake for milk supply. In addition, many women experience a distaste for meat at different points throughout pregnancy as a self-protection from potential pathogens, rendering a meat-only diet next to impossible to uphold.
Long Term Sustainability Is Difficult
Lastly, as with any restrictive diet with only a small list of specific foods, the long-term sustainability is questionable and it’s difficult to adhere to. A carnivore diet for women may be more effective as a short-term step to remedy a health woe or expedite weight loss before transitioning to a keto or paleo lifestyle.
Carnivore Diet and Menstrual Cycle Irregularities
If your diet is very restrictive, you may experience irregular menstrual cycles or amenorrhea, defined as the absence of a menstrual cycle for 3 months or more. The most common cause of amenorrhea is functional hypothalamic amenorrhea, which can result from a very low calorie diet, disordered eating, losing weight, experiencing stress, or getting too much exercise. Restricting carbs could contribute to some of these causes.
Amenorrhea occurs as a result of the drop in levels of many hormones, such as gonadotropin-releasing hormone, which starts the menstrual cycle. This results in a domino effect, causing a drop in the levels of other hormones such as luteinizing hormone, follicle-stimulating hormone, estrogen, progesterone, and testosterone. These changes can slow some functions in the hypothalamus, the region of the brain responsible for hormone release. A low level of leptin, a hormone produced by fat cells, is another potential cause of amenorrhea and irregular menstruation. Research suggests that women need a certain level of leptin to maintain normal menstrual function. If your carb or calorie consumption is too low, it may suppress your leptin levels and interfere with leptin’s ability to regulate your reproductive hormones. This is particularly true for underweight or lean women on a low carb diet.
Female athletes often underconsume in calories, especially carbohydrates, and that this can affect menstruation and other important metabolic processes. Research on amenorrhea and low carb diets is still scarce. Studies that report amenorrhea as a side effect were usually done only in women following a predominately low carb diet for a long period of time. Following a very low carb (ketogenic) diet over a long period of time may cause irregular menstrual cycles or amenorrhea.
The irregular or disappearing periods can be traced to hormone changes. Any sort of stressor - weight loss or a lot of exercise - can affect that pulsatile release that has to happen for this normal choreography of hormone release that allows you to have regular menses. Keto caused disruption to women’s hormonal systems. One of the main hormones in play here is estrogen, which is responsible for regulating the menstrual cycle. As weight drops, so do estrogen levels. Another hormone that seems to mess with period regularity is the gonadotropin-releasing hormone (GnRH). GnRH is the signal for pituitary production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are responsible for stimulating ovarian production of estrogen and progesterone, and therefore ovulation).
Carnivore Diet and Thyroid Function
Very low carb diets may cause a drop in thyroid function in some people, potentially resulting in fatigue, weight gain, and low mood.
How Many Carbs Should You Eat?
The optimal amount of dietary carbs varies for each individual. The Dietary Guidelines for Americans recommend that carbs make up 45-65% of your daily calorie intake. The Food and Drug Administration states that for a 2,000-calorie diet, the Daily Value for carbs is 275 grams per day.
Eating a moderate amount of carbs - that is, 50% to 55% of your total calories - was associated with the lowest risk of dying. Benefits of a moderate-carb diet may include weight loss, improved mood and energy levels, normal menstrual function, and better sleep. Other women, such as athletes or those trying to gain weight, may find a higher daily carb intake appropriate.
Who Might Benefit from a Low-Carb Diet?
Certain women may do better sticking to a low carb diet, including those who have:
- Overweight or obesity
- A very sedentary lifestyle
- Epilepsy
- Polycystic ovary syndrome, fibroids, or endometriosis
- Yeast overgrowth
- Insulin resistance
- Type 1 or type 2 diabetes
- A neurodegenerative condition such as Alzheimer’s disease or Parkinson’s disease
- Certain forms of cancer
Carnivore Diet and Endometriosis
Endometriosis is a chronic condition where tissue similar to the lining of the uterus (endometrium) grows outside the uterus. It can cause a variety of symptoms, including chronic pelvic pain, painful periods, heavy bleeding, irritable bowel syndrome (IBS) symptoms and difficulty getting pregnant.
There's no cure for endometriosis. However, the gold standard for treatment involves excision surgery by an endometriosis specialist. Excision surgery removes the endometriosis implants, aiming for long-term symptom relief. Diet can't treat endometriosis, but research suggests it can play a role in managing symptoms.
The Carnivore Diet for Endometriosis: Potential Pitfalls
The carnivore diet restricts everything but meat, fish, eggs, and low-lactose dairy products. While proponents claim it can improve various health conditions, no studies specifically link it to endometriosis. The carnivore diet eliminates some potential dietary triggers for endometriosis, it also cuts out critical dietary sources of beneficial nutrients. It is high in nutrients that are associated with increased endometriosis pain. High saturated fat intake: Red meat is a significant source of saturated fat. Research suggests that eating more than two servings of red meat per day may increase endometriosis pain.Trans fat intake: Intake of trans fats is associated with increased endometriosis pain. Naturally occurring trans fats are found in cow and sheep products.
Why Some People Feel Better on the Carnivore Diet
There might be a different explanation for why some people experience symptom relief on the carnivore diet: Gluten elimination: Many people with endometriosis have undiagnosed gluten sensitivity. Eliminating gluten-containing grains can improve symptoms.Reduced FODMAP intake: FODMAPs can exacerbate digestive issues that are common in endometriosis patients.Ketogenic effects: The carnivore diet induces ketosis, a state in which the body burns fat for fuel. Ketosis can improve energy and blood sugar, cause weight loss, and reduce inflammation.Potential hormone changes: Endometriosis is known to be an estrogen-dominant disease. Diets high in sugar and processed foods are associated with increased estrogen levels. Reducing these foods may lower estrogen levels and improve endometriosis symptoms.Pesticide exposure: Pesticides used in conventional farming can act as endocrine disruptors, interfering with hormone function and potentially exacerbating conditions like endometriosis. Eliminating produce and grains may reduce exposure to some of these pesticides. However, animals also come in contact with pesticides regularly.
The Dangers of Restrictive Dieting
While restricting certain foods might be helpful, long-term restrictive diets have serious downsides: Nutrient deficiencies: The carnivore diet lacks fruits, vegetables, and whole grains, which are essential for a balanced diet. The absence of plant-based foods can lead to deficiencies in essential vitamins, minerals, and fiber.Kidney and heart health risks: High saturated fat and protein intake can negatively impact kidney and heart health.Mental health issues: Highly restrictive diets can contribute to disordered eating patterns, exacerbate eating disorders, and negatively affect mental health.Sustainability issues: Long-term adherence to restrictive diets can be difficult. People may struggle with social situations, meal planning, and finding suitable food options.Feelings of failure: Not being able to stick to a strict diet can lead to feelings of failure, guilt, and decreased self-esteem.