Intermittent Fasting (IF) is a dietary trend where people alternate between eating and fasting. Typically, people fast for twelve to eighteen hours each day, then have an eating window of six to twelve hours. The long fasting period triggers the body’s fat burning mode, as you are not taking in calories to provide energy. It is thought to have a number of health benefits, including weight loss, prevention of type two diabetes, improved cognitive ability and potential longevity. Intermittent fasting tends to be very safe and manageable for men, even in its most intense forms. However, IF can have a negative impact on women’s hormonal regulation, mood and sleep pattern, leading to some quite serious health problems.
When your body experiences a fast period, it starts burning its existing fat supply for energy, which is why it works as a weight loss tool. However, women’s bodies are designed to procreate, and from an evolutionary perspective, the body wants to avoid reproduction if there is a shortage of food resources. The reproductive system can begin to malfunction, leading to disruption of periods and a total lack of menstruation, issues with fertility and even early onset menopause. Other symptoms of hormone disruption include anxiety, depression and insomnia.
These symptoms are quite serious and it is important to stop intermittent fasting if you notice any change to your menstruation, mood or sleep. One of the best ways to stay safe and protect your hormones is to keep a record of these functions for the first two or three months you try IF, and make adjustments to your approach if you notice any disruption. Some women just do not get on with intermittent fasting, and if you try a few different adaptions and techniques but still experience hormonal disregulation, the health benefits of fasting will not be outweighing that cost. In these cases, it is best to practise acceptance and stop IF completely.
However, there are some adaptions you can make to traditional IF plans to create a safer and more suitable diet for your body. It is a good idea to keep a record of your symptoms any time you make a change to your IF plan to ensure you are safe and healthy.
The First Adaption
The first adaption is to reduce the fasting period and increase your eating window. Many IF plans advocate for a sixteen to eighteen hour fasting period followed by a six to eight hour eating window. IF can be just as effective if you fast for twelve to fourteen hours, and eat for a ten to twelve hour window.
For example, if you have breakfast at 7am, lunch at midday and dinner at 7pm, then eat nothing else during the evening, you create a twelve-hour fast period. Equally, you could eat breakfast at 8am and dinner at 6pm, creating a fourteen-hour fast period. Try a twelve-hour fast period first, and if this works well for you consider increasing to a fourteen-hour fast. It does not matter what time of day you choose for your eating window. If your natural rhythm is to get up late, skip breakfast, or just eat later in the day, you could have an eating window of 10am-10pm or even 12pm-12am.
The Second Adaption
The second adaption is to fast on alternate days. Many intermittent fasters promote daily fasting for maximised effect, but this is not necessarily healthy for women. Begin by fasting for two non-consecutive days per week, then after two weeks add a third fasting day. The maximum number of fasting days should be seven out of every fourteen, so that there is always a regular day between fasts.
Every time you change the number of days, try to log any changes or symptoms in your record to ensure that you are staying healthy. Some women might find that fasting two days per week, or five days out of every seven, is their optimal IF diet. Other women may have no problem fasting for three days per week or seven out of every fourteen. Be sure to respond to any warning signs that your body is not coping with fasting and go back to a point in your plan where you were feeling healthy.
The Third Adaption
Third, you might choose to replace one meal each day with a snack that is high in fat. In place of breakfast or lunch, try eating half an avocado, a spoonful of chia seeds, a handful of nuts or a spoonful of coconut oil. Avoid any food with a high carbohydrate or sugar content as these nutrients interfere with the effects of the fast.
A high fat snack has a much lower impact on the fat burning that results from periods of fasting. Some people advocate replacing breakfast with a cup of coffee with butter and MCT oil. The fats in this drink help curb hunger cravings without interfering with the fasting process. Butter is not a nutritious food so this drink should only be consumed a maximum of once per fast day.
The Fourth Adaption
Fourth, to protect yourself as much as possible during an IF diet, try to exercise regularly. Choose low impact, gentle exercises such as yoga and walking on fast days, and keep your body strong with High Intensity Interval Training (HIIT), weight training and high impact cardio on regular days.
Keeping your muscles strong and your cardiovascular system as healthy as possible will minimise any negative impacts of IF on your reproductive system and emotional health. General advice on IF says that you can do full, intensive workouts on fast days, and as many male intermittent fasters have fasting periods every day, this makes sense. However, women should be more cautious as intensive exercise on fast days may increase the body’s need to shut down reproduction.
The Fifth Adaption
Fifth, if IF proves too challenging or not appropriate for your body, the 5:2 diet is a popular way to fast without having actual eating windows and prescribed fasting periods. To follow this diet plan, choose two days per week to eat just 500 calories then eat normally the rest of the time. The benefit of this plan is that you can spread your meals throughout the day and evening, meaning you should never have to go hungry.
The massive reduction in calories has a similar impact on your body as a complete fast, but it is less intense and more comfortable than having long fasting periods. The 5:2 diet is a good gateway into IF for those who want to ease in slowly. If the 5:2 diet is too challenging, try increasing your calorie intake to 600 or 700 calories on fast days and then gradually reduce to 500. Also, make sure you fast on non-consecutive days to give your body time to recover.
As the adapted methods may still have an impact on hormonal regulation, women who are pregnant, breastfeeding or trying to conceive should avoid any form of IF diet.
Fasting can also be very triggering for people who struggle with eating disorders as it can produce periods of hunger and feelings of deprivation. If you have ever had an eating disorder, consider consulting a doctor before starting a fasting diet, and ensure that IF would compliment a self-care regime, not disrupt it.
If you can find a way of intermittently fasting that works for you safely and effectively, you may be able to enjoy the associated health benefits of weight loss, diabetes prevention, clarity of mind and longevity. However, IF does not suit all women and if you cannot find a way to follow an IF plan whilst protecting your reproductive and emotional health, it is healthiest and safest to find a different diet plan that meets all of your needs.