Keto works in much the same way for women as for men, but a few issues matter more. Eating too little, which is easy on a restrictive diet, can disturb periods and hormones. Women have higher iron needs before the menopause, and a greater risk of osteoporosis after it, so iron, calcium and vitamin D need attention. Keto isn’t recommended during pregnancy or breastfeeding without specialist advice. On the other hand, some women with polycystic ovary syndrome (PCOS) find that a low-carb diet helps with weight and insulin resistance, and keto can help with weight loss at any age. The key is eating enough, choosing nutrient-rich foods and checking in with your doctor.
Possible benefits
- Weight loss: keto can reduce appetite, which helps some women eat less without counting calories.
- Blood sugar: cutting refined carbs often improves blood sugar control in women with insulin resistance, prediabetes or type 2 diabetes. Our guide to keto and insulin resistance explains the link.
- PCOS: see the section below.
- Fewer sugar cravings after the first few weeks, for many people.
Keto and PCOS
PCOS affects how the ovaries work and is often linked with insulin resistance. It can cause irregular periods, excess hair, acne and difficulty losing weight. The NHS recommends a healthy, balanced diet as part of treatment, along with medicines if needed. Low-carb diets have been tried for PCOS. In a small pilot study, 11 women with PCOS were asked to eat 20 g of carbs or less a day for 24 weeks. Only 5 finished, but they lost 12% of their body weight on average and their free testosterone fell by 22%. That’s promising but far from proof, and a moderate lower-carb or Mediterranean-style diet may help just as much. Talk to your doctor, especially if you take metformin or are trying to get pregnant.
Periods and hormones
Some women notice changes to their cycle on keto. The most common cause is eating too little or losing weight quickly, especially alongside a lot of exercise. When energy intake is too low for the body’s needs, it can switch off non-essential functions, including ovulation. The International Olympic Committee consensus statement on Relative Energy Deficiency in Sport describes how low energy availability can affect periods, bone health and other body systems. Signs to watch for include missed or irregular periods, constant tiredness, feeling cold and frequent injuries.
To reduce the risk:
- Eat enough. Don’t combine keto with very low calorie intake and intense training.
- Get enough protein at every meal.
- If your periods stop or change a lot, see your doctor. Don’t assume it’s just the diet.
Pregnancy and breastfeeding
Keto isn’t recommended in pregnancy without specialist advice. Pregnancy needs folate, iodine, fiber and enough carbohydrate for the growing baby, and there’s very little evidence on keto in pregnancy. Breastfeeding increases energy needs, and there are rare reports of ketoacidosis in breastfeeding women on very low-carb diets, such as one case report from Sweden in a woman without diabetes. Our guide to keto during pregnancy explains the concerns, and if you’re planning a pregnancy, talk to your doctor about your diet and supplements.
Iron
Women who have periods need more iron than men: 14.8 mg a day for women aged 19 to 50 compared with 8.7 mg for men, according to the NHS. Keto cuts out fortified cereals and beans, two important iron sources. Red meat, liver, seafood, eggs, pumpkin seeds, spinach and other leafy greens help. Signs of iron deficiency include tiredness, shortness of breath and pale skin. Our list of iron-rich foods has more.
Bone health and menopause
After the menopause, falling estrogen speeds up bone loss and raises the risk of osteoporosis. The NHS recommends enough calcium and vitamin D, along with weight-bearing and strength exercise. On keto, include dairy such as cheese, Greek yogurt and milk in your carb allowance, or calcium-rich alternatives such as canned sardines with bones, almonds and leafy greens. Many women also need a vitamin D supplement in winter.
The menopause can also make weight gain around the middle more likely. Some women use keto to manage this; others find a Mediterranean-style diet easier to keep up. Our menopause diet guide covers the options.
Cholesterol and heart health
LDL cholesterol rises in some people on keto. Women’s heart disease risk increases after the menopause, so it’s worth having your cholesterol checked before starting and after a few months. In a randomized trial comparing keto with a Mediterranean diet, LDL rose by about 10% on keto. Choosing olive oil, nuts, avocado and oily fish over butter, cream and processed meat helps. Our guide to keto and cholesterol explains more.
Exercise
Strength training helps preserve muscle and bone during weight loss. High-intensity exercise may feel harder in the first few weeks of keto while your body adapts. Our guide to keto and exercise has tips.
A sample day for women on keto
- Breakfast: Greek yogurt with raspberries, chia seeds and a few walnuts.
- Lunch: spinach salad with salmon, avocado, pumpkin seeds, feta and olive oil dressing.
- Snack: a boiled egg and cucumber sticks.
- Dinner: steak or tofu with broccoli, mushrooms and cauliflower mash.
This gives protein at every meal, iron from steak, spinach and pumpkin seeds, calcium from yogurt and feta, and plenty of fiber from vegetables and seeds.
Common questions
Is keto safe for women?
For many healthy women, keto is safe in the short term with good food choices and enough calories. It isn’t suitable for everyone, including pregnant women, people with certain medical conditions, and anyone with a history of eating disorders.
Does keto affect fertility?
Losing weight can improve fertility in women with PCOS who are overweight, while eating too little can reduce it. If you’re trying to conceive, talk to your doctor before starting any restrictive diet.
Why am I losing hair on keto?
Rapid weight loss can trigger temporary hair shedding a few months later. Eating enough protein and calories helps. Our guide to keto side effects covers this and others.
Safety note: Keto isn’t suitable for everyone. If you have diabetes, kidney or liver disease, take regular medication, or are pregnant or breastfeeding, talk to your doctor before cutting carbs this far (why it matters).
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
