As nutritional ketosis or “keto” grows in popularity, I see more women struggle with it. Certainly, there are some people who go on the keto diet, see all the benefits of mental acuity and fat loss, and none of the problems. More men than women experience this level of keto success. Then there are the rest of us.
My anecdotal observation in my medical office and working with people online is that men perform better in nutritional ketosis compared with women, particularly women aged 40 and older. My female patients, myself included, have more problems on keto with their stress hormones (i.e. producing too much cortisol), thyroid function, and may develop menstrual irregularities. At the root of these problems is dysfunction of the control system for hormones, the hypothalamic-pituitary-adrenal-thyroid-gonadal (HPATG) axis.
Some women do fine on the ketogenic diet, others may feel worse, suffer from mood issues, and can even gain weight, as a result of metabolic stress and inflammation. Additionally, there are at least ten genetic variations that may make a person less likely to benefit from keto. In other words, keto can be complicated.
Backstory on the Ketogenic Diet
Nutritional ketosis has been used to treat epilepsy since the 1920’s and its popularity for mental acuity and weight loss has surged recently. Ketosis refers to a metabolic state in which most of your body’s energy comes from ketones in the blood, as opposed to glycolysis, in which energy supply comes from blood glucose. Ketones are made in the liver when there are not enough carbohydrates to be burned for energy demand, so the body turns to fat for energy. The body enters ketosis when blood sugar levels are below a certain level, and liver glycogen is no longer available to produce glucose for energy.
Ketones are an efficient fuel for the brain—sometimes more efficient than glucose—which is why it is touted as the optimal diet for people with neurodegenerative or “brain body” conditions such as brain fog, attention deficit disorder, epilepsy, multiple sclerosis, Parkinson’s disease, traumatic brain injury, mild cognitive impairment, and Alzheimer’s disease. Most of my patients when in ketosis tell me that they feel smarter, sharper, and more focused—and some may lose weight (fat) as a result of using ketones as fuel and developing metabolic flexibility.
(Note that ketosis should not be confused with diabetic ketoacidosis, a dangerous state that occurs primarily in Type 1 and sometimes in Type 2 diabetics, when high levels of ketones build up because there’s not enough insulin to metabolize blood glucose—so the diabetes becomes out of control. This is sometimes due to an infection or other severe stress. But for healthy individuals without Type 1 diabetes, ketones are used as an alternative energy source and rarely poison or acidify the body.)
Ketogenic Diet Basics
Here are the guidelines:
- Eat fewer carbohydrates, about 5 to 10 percent of total calories (aim for 20 to 50 grams per day, and adjust to find your carb threshold)
- Consume more healthy fat, about 60 to 80 percent of total calories, mostly plant- and fish-based. Think avocados, coconuts, medium chain triglyceride oils, and wild fish. Even though many keto devotees sing the praises of bacon, lard, and recipes for meals like keto lasagna, I believe the evidence is better for plant- and fish-based sources. (Just be careful to get the selenium and mercury ratio right in your fish—see references.)
- Limit protein to about 20 percent of total calories, or the minimum needed to preserve muscle mass. (The advanced version requires that you perform body composition analysis in order to track your lean body mass and fat mass. I use the Renpho bathroom scale and app, plus perform a BOD POD once per quarter.)
Keto can promote fat loss—in the right person. For people who are sugar burners and can’t kick their sugar cravings, keto can be very helpful, because the increased fat is satisfying and curbs sugar cravings, and people eat less overall compared to their baseline diet. I occasionally prescribe it for weight (fat) loss, and for help with specific hormone imbalances involving insulin and stubborn fat gain because it can improve insulin sensitivity. This includes patients struggling with the following: obesity, weight-loss resistance (assuming the thyroid is healthy), metabolic syndrome, and PCOS with insulin resistance and weight gain. Aside from these specific health conditions, I believe we have to tweak the keto diet a little more for success in women. We are not simply smaller versions of men, and our hormones require more support. Women with HPATG axis dysregulation commonly require more healthy carbohydrates.
Men consistently respond better to low-carb and keto by becoming more sensitive to insulin. In one study, a low-carb diet led to a 37-percent reduction in insulin, which accounted for 70 percent of the male participants’ weight loss. I’m not yet convinced this is true for all women.
The optimal carbohydrate level for you can vary over the years, such as when you’re more active physically or breastfeeding or stressed. To be safe, eat the most carbs that you can tolerate while staying in ketosis and regulating your blood sugar. I urge caution and that you work with your healthcare professional.
How Do You Know You’re in Ketosis?
You know you’re in ketosis by checking blood ketones with a hand-held ketone meter (a test for beta-hydroxybutyrate). A ketone meter can be purchased online for about $100-120, along with ketone test strips, which tend to be pricey. You prick your finger and use a drop or two of blood to measure ketones. Aim for 0.5-3.0 mm. I use KETO-MOJO, which can check for both ketones and glucose in the blood (useful if you’re overweight). Some people measure ketones in the urine or via a breath taste, but I’ve found them to be not as accurate. As always, if you’re unsure or are having trouble with adapting to ketosis, the safest strategy is always to work in consultation with a health care practitioner.
How Long Is Keto Safe?
I suggest trying nutritional ketosis for 6-12 weeks and testing your blood and urine with a functional medicine panel to see if it’s a good fit. With a collaborative clinician, look at inflammation, cholesterol, adrenal, and thyroid function.
That’s why it’s important to work with a knowledgeable clinician who can guide your experience and keep you safe. Keep asking the question, Is ketosis right for me? There are the obvious measures to track—weight, body fat, aches and pains, menstrual pattern, and other hormone symptoms. Note that up to 45 percent of adolescent females have menstrual irregularities on the ketogenic diet. I also monitor the following in my patients on ketosis:
- Cholesterol (with an advanced panel that includes fractionated LDL and HDL)
- Fasting glucose and hemoglobin A1C (like a three-month snapshot of blood sugar)
- Inflammation (C-reactive protein, homocysteine)
- Thyroid function (with an expanded thyroid panel, including TSH, free T3, reverse T3, free T4)
- Sex hormones (cortisol, estrogen, progesterone, testosterone)
- Electrolytes and minerals (sodium, potassium, magnesium, copper, zinc, selenium)
- Sex hormones including cortisol and estrogen metabolism, such as the DUTCH test from Precision Analytics
- Organic acid testing (OAT), such as by Great Plains Lab
Stop ketosis if lipids shift in the wrong direction, inflammation increases over baseline, hormones become more out of whack, blood sugar worsens, electrolytes are abnormal, or fat mass increases. Replete any abnormal electrolytes or mineral levels; most people in ketosis take electrolyte supplements.
After you’re stable in ketosis based on blood monitoring, try adding more carbs in the form of vegetables to define your threshold.
At this point, we don’t know how long is safe to remain in ketosis. Based on the clinical trials, I recommend a trial of ketosis for up to 6 months, under the care of a knowledgeable functional medicine physician. There are some clinical trials up to 12 months, so that would be the maximum I would recommend under the watchful eyes of a collaborative professional and expert.
Benefits of the Keto Diet
Keto is a healthy state for some, but not all. It is most proven for epilepsy and other brain problems like Alzheimer’s disease. There are more safety concerns for people trying keto for fat loss or performance. In humans, there are reports of adverse reactions to keto, including menstrual irregularities, gut dysbiosis, change in circadian rhythm, hair loss, constipation, mood disorders, and thyroid dysfunction; and in rodents, insulin resistance and nonalcoholic fatty liver.
Regarding weight loss, one of the benefits of keto is that seems to suppress appetite.
Beyond the fat loss and the conditions mentioned previously that are associated with inflammation in the brain body, nutritional ketosis has been shown to help prevent and starve cancer cells (see studies referenced below). Ketosis improves certain forms of cellular healing, including mitochondrial biogenesis (the making of new, bigger, and higher energy-producing mitochondria), so that your cells are stronger and have more stamina, particularly when it comes to exercise. For example, some endurance and ultra-endurance athletes believe that their performance improves in nutritional ketosis compared to sugar burning, when they have more fat than carb reserves. But because of the limited data, and available data suggesting that athletes may actually perform worse on nutritional ketosis, I do not currently recommend it for elite athletes.
Ways to Make Keto More Friendly to Women
For women, I recommend testing the HPATG and making sure it is optimized before embarking on a ketogenic diet. See the recommended testing mentioned previously.
Women make up the majority of the diagnoses of Alzheimer’s disease, and I believe that is a more compelling reason to try the keto diet than weight loss.
As an alternative or adjunct to the keto diet, consider intermittent fasting. It is a simpler way to achieve mild and cyclic ketosis and has many of the same benefits. Anecdotally, it has worked better for me for weight loss than nutritional ketosis, without inflammation and excess cortisol load. I prefer a 16/8 protocol, where you confine eating (with no change in calories) to an 8-hour window, then fast overnight. For instance, I finish eating by 6 p.m., then eat again at 10 a.m. the next day. For weight loss, I recommend following this protocol two or more days per week, and show you how to dial in the number of days in our new course, tentatively titled: WOMEN, INTERMITTENT FASTING, KETOGENIC DIET, CYCLIC KETO: WHAT WORKS?! Sign up here to be the first to hear when it drops this fall.
Few people perform intermittent fasting correctly, which is why I’m offering an online course on how to do it with special modifications for women and our unique health issues.
While I’ve seen the keto diet work for some people, at the end of the day, the most important thing is that you feel good whatever eating style you’ve chosen. Experimentation and personalizing your diet to your specific needs is the winning combination. What works for some people won’t work for others. What works for you now may not work for you next year.
My evidence-based advice is to keep your food plan in balance—eat mostly vegetables (about 1-2 pounds per day), eat the minimum anti-inflammatory protein to preserve lean body mass, avoid processed foods and those that inflame you, and track your body composition over time. Use an elimination/provocation diet to discover the foods that suit you best, and to develop a personalized food code. (We will show you how in the new online course.) Extreme works for some people, but not for me, and not for all women.
Now it’s your turn. Have you tried the ketogenic diet? Did it work for you? If yes, what were your outcomes? If no, what problems did you encounter?
Kindly respond in the comments below! Your insights and experiences really help me and others understand the biological underpinnings better. Thank you, SG.
- Alzheimer’s disease: Alzheimer’s and Dementia, Annals of NY Academy of Sciences, Biomed Research International, EbioMedicine, The Lancet Neurology
- Athletes and macronutrients/keto diet: Journal of International Society of Sports Nutrition, Journal of Sports Medicine & Physical Fitness
- Women, keto diet, and low carbohydrates: Current Pharmaceutical Design, Epilepsia, Nutrients
- Epilepsy: Clinical Nutrition ESPEN, Epilepsia (adolescents and adults)
- Thyroid: Clinical Endocrinology, International Journal of Obesity, The American Journal of Clinical Nutrition (and here)
- Cancer: Cureus, Epilepsy Research, International Journal of Preventative Medicine, Nutrition & Metabolism (and brain cancer)
- Selenium, mercury, and fish: Biological Trace Element Research, EcoHealth, Environmental Science & Technology, Journal of Trace Elements in Medicine and Biology, Toxicology
- Effects of nutritional ketosis on weight, insulin, appetite, and health: American Journal of Physiology-Endocrinology and Metabolism, Journal of Pediatric Endocrinology and Metabolism, Endocrine, Nutrients, The Journal of Clinical Endocrinology & Metabolism (and here), Obesity Reviews
- Intermittent fasting: Annual Review of Nutrition, Epilepsy & Behavior, Epilepsy Research, PLoS ONE