Is intermittent fasting the new buzz or are there actual health benefits associated with it. And are these studied benefits appropriate for the female body?
Let’s dive in.
Observing the rise in intermittent fasting with clients over the last few years, it is very important to consider if this type of diet is right for you and your body’s needs – in particular, the woman’s body.
What is Intermittent Fasting?
Intermittent fasting is an eating pattern that cycles between periods of eating and fasting. There are different types of methods which all include alternate days or set hours in the day. This may look like:
- 5:2 method which includes restricting calories to 500-600 twice a week
- 16/8 method which includes fasting for 16 hours and an eating window of 8 hours
- Eating first meal at noon and so on
Permitted during fasting window are non-caloric drinks such as water, teas and coffees. Supplements are also allowed.
What are the Suggested Health Benefits?
Studies suggest (but not limited to) below health benefits of intermittent fasting:
- Weight loss and management
- Enhanced cardiovascular health
- Improved brain health
- Inflammation and oxidative stress reduction
- Possible cancer prevention
- Possible increased lifespan
What does the Evidence state?
A study conducted in 2021 observed a group of 43 healthy adult males in an 8-week treatment program included intermittent fasting as part of their diet along with sleep, exercise, relaxation guidance, supplemental probiotics and phytonutrients. “The diet and lifestyle treatment was associated with a 3.23 years decrease in DNAmAge compared with controls”. A few things here:
- There were many other variables added to the study e.g. sleep, exercise, relaxation guidance, and supplemental probiotics and phytonutrients
- The study group is very small with only 43 people
- It is 100% male
- An 8 week period is a short period of time
Another study in 2012 observed 29 healthy women (and 21 healthy males) during Ramadan. “Results indicate that RIF attenuates inflammatory status of the body by suppressing proinflammatory cytokine expression and decreasing body fat and circulating levels of leukocytes”. In other words, a positive sign of body fat loss and reduction in inflammation.
However, a 2017 study observed something quite different in 9 healthy women. Results presented “increased feelings of hunger, worse mood, heightened irritability, difficulties concentrating, increased fatigue, eating-related thoughts, fear of loss of control and overeating during non-restricted days”.
Recent research seems positive for obese and overweight women for weight loss however research and positive benefits for other groups of women is lacking.
It’s important to note while going through studies and seeing the promising benefits, these studies were mostly done on the male body and animals. The female body operates differently, and it would be great to see more studies with larger female sample sizes.
With the small sample of women and intermittent fasting, there seems to be solid evidence for weight loss and weight management in obese women however there are many other approaches to reach this goal e.g. daily physical movement. In fact, most intermittent fasting studies also incorporated movement within the study. In other words, is it possible the movement alone is enough to begin with?
Who Should Avoid Intermittent Fasting?
A reminder that there is no one diet that fits all. And while intermittent fasting may benefit some, it may also hinder others. Conditions where intermittent fasting should be avoided can include:
- Pregnant and Breastfeeding women: for the obvious safety reasons.
- Menstrual cycle and hormonal imbalances: restrictive eating may cause hormonal imbalances including irregular menstruation.
- Eating disorder or history of an eating disorder: a diet related to control and restriction around food may not serve someone with any type of eating disorder as it has the potential to reopen an unhealthy/traumatic relationship with food
- Diabetics and imbalanced blood glucose levels: the risk of hypoglycaemia
- Hashimoto’s: a reduction in thyroid hormones T4, T3 and TSH has been shown with periods of fasting along with blood glucose levels, which is an added stressor on the body.
- Teenagers and children
Do I personally Recommend Intermittent Fasting?
Yes and No. Hear me out….
Women have nutrient and energy requirements that change throughout the month due to our cyclical nature. Daily restriction of calories may cause a number of issues including hormonal and metabolic.
If you’ve been following me for a while you will notice I have supported and advocated for extended/prolonged fasting for the last decade. This differs to intermittent fasting as the intermittent fasting window is much smaller than the extended/prolonged fasting. Due to this reason the key difference is that the autophagy benefits are not achieved while intermittent fasting. It also may not be beneficial to encounter the stress response from fasting on a daily basis.
That does not mean some people can’t benefit from the reasons stated above however there are many other ways to reach the above benefits without potentially interfering with the female body’s rhythm and needs on a daily basis.
Intermittent fasting could be a great tool to ease someone into prolonged/extended fasting for deep detoxification benefits (this requires its own blog posts).
I would also like to see longer term studies as the body always adapts, and so if the set point (BMR) in a body changes and reduces then at some point a plateau will be reached and what was once a caloric intake for weight loss can change to a caloric surplus due to this change in set point.
I personally encourage clients to tune in with their body and notice how they may feel and function as there is no one diet for all. For more personalised advice, a qualified health professional can help with your individualised needs.
Sources
- Lange MG, et al, 2023, Metabolic changes following intermittent fasting: A rapid review of systematic reviews, https://pubmed.ncbi.nlm.nih.gov/37786321/
- Longo VD, et al, 2021, Intermittent and periodic fasting, longevity and disease,
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8932957/ - Patterson RE, et al. (2015). Intermittent fasting and human metabolic health.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4516560/ - Visioli F et al, 2022, Traditional and medical applications of fasting.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8838777/ - Yuan X, et al, 2022, Effect of intermittent fasting diet on glucose and lipid metabolism and insulin resistance in patients with impaired glucose and lipid metabolism: A systematic review and meta-analysis, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8970877/
- Cabo RD et al, 2019, Effects of intermittent fasting on health, aging, and disease.
https://www.nejm.org/doi/full/10.1056/nejmra1905136 - Dote-Montero M, et al, 2022, Effects of intermittent fasting on cardiometabolic health: An energy metabolism perspective.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8839160/ - Fitzgerald KN, et al, 2021, Potential reversal of epigenetic age using a diet and lifestyle intervention: A pilot randomized clinical trial.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8064200/ - Hollstein T, et al, 2022, Effects of short-term fasting on ghrelin/GH/IGF-1 axis in healthy humans: The role of ghrelin in the thrifty phenotype.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9387714/ - Keenan S, et al, 2022, The effects of intermittent fasting and continuous energy restriction with exercise on cardiometabolic biomarkers, dietary compliance, and perceived hunger and mood: Secondary outcomes of a randomised, controlled trial.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9370806/ - Mo'ez Al-Islam et al, 2012, Intermittent fasting during Ramadan attenuates proinflammatory cytokines and immune cells in healthy subjects, Nutrition Research, Volume 32, Issue 12, Pages 947-955, ISSN 0271-5317, https://doi.org/10.1016/j.nutres.2012.06.021
- Harvie Michelle, Anthony Howell, 2017, "Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence" Behavioral Sciences 7, no. 1: 4. https://doi.org/10.3390/bs7010004