You’ve almost definitely heard about intermittent fasting, which has become increasingly popular in the wellness world over the past few years. Intermittent fasting is a broad term that covers a range of different eating approaches, all of which restrict the period during which you eat.
Gentler versions of intermittent fasting advocate for simply eating in a 12 hour window, usually finishing your last meal by 7pm. Other more extreme versions call for far longer fasting windows (like 18:6 or 20:4), or severe calorie restriction. OMAD is an acronym for One-Meal-A-Day, a type of intermittent fasting that restricts calorie intake to a single meal or a very brief window of time.¹ The 5:2 version of intermittent fasting limits daily calorie intake to 500 calories twice per week, and unrestricted eating the other five days of the week.²
Generally speaking, all versions of intermittent fasting are aimed at the same set of goals: weight loss, increased energy, gut health, and mental clarity. But because of its relatively broad definition and varying extremes, not all forms of intermittent fasting are safe for all people, and women, in particular, have special considerations to take into account when it comes to this lifestyle change. Those who are pregnant or breastfeeding, anyone with a history of disordered eating or who is currently underweight, and those dealing with chronic elevated stress should steer clear of any food-restricted eating plans.³
Dr. Amy Shah, a double-board certified MD in immunology and internal medicine, advocates for a specific type of intermittent fasting for women: circadian fasting. The basic idea is that you restrict your eating period based on your natural wake/sleep cycle, which should be active and eating during the day, resting and digesting in the evening and through the night. Dr. Shah explains that this type of eating can bring the body back into balance, improving hormonal health, gut health, and brain health.⁴
In order to reap the benefits of circadian fasting, your fasting window should be at least twelve hours, which is how long it takes for your body to switch from using sugar to using fatty acids for fuel. Adding slightly more time can bring even greater benefits, but Dr. Shah says it doesn’t have to be all or nothing. If you’re “really feeling it” you can go for 16:8 one day then revert to 12:12 the next.⁵
If you’re interested in giving circadian fasting a try, here are some helpful hints to get you started:
- Start Small - Dr. Shah warns that the increased stress that fasting puts on the body has the potential to negatively affect your hormonal cycle, which can undermine the health benefits you’re looking to gain. Try starting with one or two days a week, or a longer fasting window (like 12 hours), then slowly finding the sweet spot for your body.
- Listen to Your Body - It may be beneficial to keep a journal as you start to introduce circadian fasting into your routine so you can be on the lookout for changes, both positive and negative. You are the best expert on your body, so make adjustments as necessary to keep you feeling your best.
- Adjust for Your Period - Dr. Shah suggests that women may need to adjust for their period, especially in the week leading up to menstruation. This is the time when your body is most sensitive to extra stress, so you may want to eat during a 12 hour window, as opposed to a 10 hour window.
- Eat Nutrient Dense Foods - When you’re eating is the primary focus of intermittent fasting but what you’re eating still has a huge impact on your health. Eating nutrient dense foods during your eating hours such as nuts and seeds, dark leafy greens, and omega-3 rich salmon can help support your hormones as well.
At the end of the day everyone knows their body best so keep that in mind as you make changes to your lifestyle. Also, make sure to keep your doctor in the loop about any changes to your eating habits, including fasting. Take note of how you feel as you try fasting and make choices that align with your body’s needs.
Cheers to healthy & happy hormones,
¹ Is Eating One Meal a Day a Safe and Effective Way to Lose Weight?
² Beginner's Guide to the 5:2 Diet
³ Is Intermittent Fasting Safe For Women?
⁴ Dr. Amy Shah on Circadian Fasting
⁵ Dr. Amy Shah on Circadian Fasting