Intermittent fasting for women: does it work, and is it safe?

Intermittent fasting can help some women lose weight, but it works about as well as ordinary healthy eating, not better. A 2026 Cochrane review of 22 trials found little to no difference in weight loss compared with regular diet advice. It helps only if it leads you to eat less overall without overeating later. Keep protein up, strength train, and don’t try it without medical advice if you are pregnant, breastfeeding, have had an eating disorder or have diabetes treated with insulin or similar medicines.

What is intermittent fasting?

Intermittent fasting means eating only at certain times. The common types are:

• Time-restricted eating (such as 16:8): eating within a daily window, for example 8 hours, and fasting for the other 16.
• 5:2: eating normally on 5 days and very little on 2 days a week.
• Alternate-day fasting: fasting or eating very little every other day.

Does it work for weight loss?

The best evidence says it works, but no better than other ways of eating less.

• Cochrane review, 2026: 22 randomised trials with 1,995 adults with overweight or obesity. Compared with regular dietary advice, intermittent fasting made little to no difference to weight loss, and it may make little to no difference to side effects, although the evidence was low or very low certainty. The reviewers suggested that people judge it on how practical and sustainable it is for them.
• A 12-month trial in China (2022): 139 adults with obesity all followed a calorie-reduced diet; half also ate only between 8 am and 4 pm. After a year, the eating-window group had lost 8.0 kg and the calorie-only group 6.3 kg, a difference too small to be sure it was real. Waist, body fat and blood tests were similar.
• A 12-week 16:8 trial in the US (2020): 116 adults ate either from noon to 8 pm or three regular meals. Weight loss was not different between the groups, and in the group tested in person, the fasting group lost slightly more lean mass in the arms and legs.

In short: fasting is one way to eat less, not a special fat-burning trick. For the plan that works for most women, read how to lose weight as an Indian woman.

Is it different for women?

Very few studies have looked at women’s hormones. A 2022 review of human trials found that in premenopausal women with obesity, intermittent fasting lowered androgen (male hormone) markers and did not change oestrogen or other reproductive hormones. The authors were clear that there are too few studies for firm conclusions.

What matters in practice: if your periods become irregular or stop while fasting, stop and see your doctor. The NHS lists sudden weight loss and stress among the causes of missed periods. For PCOS, the international guideline says no single eating pattern is best, so choose one you can keep; see our PCOS diet guide.

Who should not try it without medical advice

• Pregnant or breastfeeding women: this is not a time for weight-loss fasting. Diabetes UK notes that people who are pregnant, unwell or elderly aren’t usually expected to take part in religious fasting either.
• Women with diabetes, especially if you use insulin or medicines that can cause low blood sugar (hypos). Diabetes UK advises talking to your healthcare team before any fast, and breaking the fast straight away if you have a hypo.
• Anyone who has had an eating disorder, or who finds that fasting leads to binge eating. Please talk to a doctor, or call Tele-MANAS on 14416.
• Women taking regular medicines that need to be taken with food, or with a health condition: ask your doctor first.
• Teenagers, who need regular meals for growth.

If you want to try it: a gentle approach

1. Start with 12 hours overnight: dinner by 8 pm and breakfast at 8 am. Only shorten the window if you feel well.
2. Eat proper meals in your window: dal, sabzi, roti or rice, curd, and protein at every meal. ICMR-NIN advises that weight-loss diets should not go below 1,000 kcal a day.
3. Don’t make up for it with fried or sweet food when the window opens.
4. Strength train 2 to 3 times a week to protect muscle; exercise helps preserve muscle during weight loss.
5. Drink water through the fasting hours.
6. Stop if you feel dizzy, faint or unusually tired, if your periods change, or if you start bingeing.

Vrat, Navratri and religious fasts

Fasting is an important part of faith for many women, and it is a personal choice. Diabetes UK notes that people who are pregnant, unwell or elderly, or who treat diabetes with insulin, aren’t usually expected to fast for health reasons, and that anyone unsure should talk to their healthcare team and spiritual guide. If you do fast:

• Choose roasted, boiled and curd-based foods more often: roasted makhana, fruit, curd or raita, paneer, and kuttu, singhara or rajgira rotis made with little oil.
• Go easy on fried vrat food: sabudana vada, kuttu puri, pakoras and fried chips add up quickly.
• Drink enough fluids if your fast allows it: water, nimbu pani, chaas or coconut water.
• Keep moving gently: a walk or a lighter workout on fasting days, rather than intense exercise.
• With diabetes: follow your doctor’s advice on medicines and sugar checks, and break the fast if you have a hypo.

A few days of fasting is not a weight-loss plan; lasting results come from the habits you keep the rest of the year.

When to see a doctor

• Your periods become irregular or stop.
• You feel dizzy, faint, shaky or confused while fasting; with diabetes, these can be signs of a hypo.
• You have diabetes, a heart condition or take regular medicines, before starting any fasting plan.
• Fasting leads to bingeing, guilt or eating that feels out of control. Our emotional eating guide can help, and Tele-MANAS (14416) is free.

Sources

1. Garegnani LI et al. Intermittent fasting for adults with overweight or obesity. Cochrane Database Syst Rev. 2026;2(2):CD015610.
2. Liu D et al. Calorie restriction with or without time-restricted eating in weight loss. N Engl J Med. 2022;386(16):1495-1504.
3. Lowe DA et al. Effects of time-restricted eating on weight loss and other metabolic parameters in women and men with overweight and obesity: the TREAT randomized clinical trial. JAMA Intern Med. 2020;180(11):1491-1499.
4. Cienfuegos S et al. Effect of intermittent fasting on reproductive hormone levels in females and males: a review of human trials. Nutrients. 2022;14(11):2343.
5. Teede HJ et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab. 2023.
6. Diabetes UK. Religious fasting and diabetes (reviewed 28 August 2026).
7. ICMR-National Institute of Nutrition. Dietary Guidelines for Indians (2024).
8. Cava E, Yeat NC, Mittendorfer B. Preserving healthy muscle during weight loss. Adv Nutr. 2017;8(3):511-519.
9. NHS. Stopped or missed periods (reviewed 12 June 2026).
10. NHS. Binge eating disorder: overview (reviewed 17 July 2023).
11. Press Information Bureau, Government of India. Tele-MANAS (Tele Mental Health Assistance and Networking Across States) launched.

How we write our guides: read our editorial and evidence policy.