Due to different hormonal profiles, women have to take some special considerations when intermittent fasting. For women, fasting creates a major reduction of Kisspeptin, which is a precursor to reproductive hormones. Therefore, fasting can lead to a significant decrease in sex hormone production in women, which can cause a whole host of symptoms including hormonal imbalances, loss of menstrual cycle, infertility, or thyroid issues.Women also produce less leptin than men, which means that they are more sensitive to hunger when food intake is restricted.
So, should women try intermittent fasting at all?
It depends. Fasting is not a good idea for women who are very lean (under18% body fat) and/or extremely active, have subclinical hypothyroidism, have hormone disorders, have a history of an eating disorder, or are pregnant, breastfeeding, or trying to conceive.
Healthy women typically do best with shorter or less frequent fasts, such as:
- The Crescendo Method, which involves fasting for 12-16 hours 2-3 days a week on non-consecutive days. Ideally, fasting would fall on rest days as opposed to training days.
- Eat-STOP-Eat, 24-hour fasts once every 1-2 weeks. Occasional ProlongedFasting, like a Fasting-Mimicking Diet or an Elemental Diet for 3-5 days, done 1-4 times per year.
Here are some other tips on how women can take advantage of the potent benefits of fasting without sabotaging their hormones:
1. Avoid intense exercise like CrossFit and long-distance running during fasting. Opt instead for low-rep strength training, low-intensity cardio like hiking or swimming, and restorative movement like yoga and pilates.
2. Sleep, ensure you're doing everything possible to get plenty of quality nighttime rest.
3. Minimize stress, and prioritize relaxing activities.
4. Eat adequate calories from nourishing foods during feeding windows, including plenty of healthy fats to optimize hormone production.
Intermittent Fasting Mistakes
Fasting can be a great tool in the right context, but it’s ultimately a stressor on the body. When combined with others stressors such as extreme calorie restriction, intense exercise, or stressful life situations, fasting might do more harm than good for your health. Consider augmenting your fasting routine, or ditching it altogether, if you experience any of the following symptoms:
- Irregular menstrual cycles or loss of period
- Decreased fitness performance or recovery
- Poor sleep
- Negative changes to mood
- Binge eating or uncontrollable cravings
- Inability to lose weight
- Acne or dry skin
- Loss of libido
- Always feeling cold
- Thinning hair or hair loss
Intermittent fasting should be icing on the cake of an overall healthy lifestyle. Make sure you cover your bases by eating nutritious foods, getting good sleep, exercising intelligently, and managing lifestyle stress before incorporating it into your daily life.