Intermittent Fasting for Women: Pros and Cons
Intermittent Fasting is all the rage right now and If you’re reading this you have probably already heard someone raving about it! To be quite honest, personally I am not a fan but only because I genuinely believe in intuitive eating. My good friend on the other hand, swears by it! However, today I to tell you the Pros and Cons of intermittent fasting for women without a biased outlook! I believe you always should make your own decisions, especially when it comes to knowing what is right for your lifestyle and body. I just want to show you the REAL positives and negatives before you decide wether Intermittent fasting is the right fit for you. Quite often, when we read about IF fasting it is someone either defending why they do or they don't. That isn’t very helpful. I am giving you an outside perspective on intermittent fasting. Most importantly, I am focusing on IF for women ONLY. Because our bodies work differently! We have to take our hormonal health into concern when trying any diet. SO lets talk the Cons first!
CON #1: Effects on Reproductive Health and Hormones
As women with PCOS (hormonal syndrome), our reproductive health is essential, and a couple of studies show that intermittent fasting (IF) can impact it negatively. Starvation causes our body to go into survival mode which takes energy away from ovulation. One study in 2013 (1) put rats on alternate-day fasting where they completely fasted every other day and ate as much as they needed on the alternate days for a total of 12 weeks. The estrous cycle (rat equivalent to our menstrual cycle) was disrupted after just 10 to 15 days of fasting. Want to hear something shocking? The size of the ovaries decreased in female rats, and testosterone levels in male rats dropped! Another study (2) put normal-weight women on a 3-day fast before ovulation and found a significant decrease in luteinizing hormone, a hormone needed for ovulation. Currently, research is limited on human subjects and studies are only conducted over short periods. I understand you want to try IF to lose weight, but our reproductive health depends on us staying nourished with enough protein (9), vitamins, and minerals during our child-bearing years (3). In my personal opinion, this is why intermittent fasting isn’t for me. I already had so many issues with getting my hormones balanced with PCOS, if there is even a tiny chance intermittent fasting can effect my hormones, I wont try it! I also wouldn’t try it because once I get pregnant, I wouldn’t do intermittent fasting due to a possibility of hypoglycemia and to me, I always want a way of eating I could do all life long, rather than temporarily.
CON #2: Potential Binge Eating
Intermittent fasting is focused on meal timing and often also calorie restriction which can cause hunger, lowered energy, (3) and a desire to binge whenever your eating window opens up (4). Studies with normal weight women found that IF caused tiredness, overeating, hunger, and mood swings (9). These symptoms are no surprise since you’re often cutting calories and restricting meal times! If you are someone who is dealing with overeating or binge eating already and you do not have healthy relationship with food, intermittent fasting wont be the solution. Especially, if you find that you are very hungry during the fasting window. It can exacerbate the restrict then binge cycle which is very hard to get out of!
CON #3: Not Suitable for People with Diabetes
Intermittent fasting is NOT recommended for anyone with Type 1 or Type 2 diabetes, because it can cause hypoglycemia during periods of fasting (3). It is more important to take your medications, stay physically active, and keep your blood glucose levels steady. Also, if you are taking any medication to manage your insulin resistance, talk to your doctor FIRST. It may or may not be the right diet for you.
Ok, now let’s talk about the positives of IF!
PRO #1: Weight Loss
Of course, most people try IF to lose weight. A review 5 found women on a 26-week IF lost weight and body fat. Participants in another study (6) had an 8-hour eating window per day and lost weight and reduced blood pressure without counting calories. Apparently, alternate-day fasting only causes people to eat 10% more of their usual calories on regular days (7) which still results in overall lowered caloric intake resulting in weight loss. Note that these studies rarely follow-up with participants afterwards to see if IF lifestyle was effectively maintained. We still need studies to check the long- term effects.
PRO #2: Ease and Flexibility
Compared to other diets, IF is probably the easiest one to follow, especially if you implement the time-restricted 8-hour per day eating window with three meals and no snacks. IF is focused on meal timing and does not restrict you to specific diets or food rules. However to be honest, for best results, is is important to pair the meal schedule with a balanced diet of whole grains, fruits, vegetables, legumes, and lean protein, and stay physically active.
Pro #3: Physical Activity and Metabolic Rate Not Affected
We’ve all tried a restrictive diet that drained our energy making it hard to exercise. Studies have shown physical activity and metabolic rate is not affected with IF. People are able to maintain their physical activity levels by working out before their meals (7). Here’s a fascinating find: Out of your weight loss from other diets, 25% of it is muscle loss. With IF, the muscle loss is only 10% which is great for your metabolic rate (7). Obese individuals on IF continuously attended their planned exercise program (8). So if you’re looking to make a lifestyle change while prioritizing exercise, IF may be worth a try.
Wether Intermittent fasting is for you or not truly depends on what is of importance to you. It does show weight loss but may effect our hormones. If you really want to try it, start with a shorter fasting window and see how you feel. It is a new popular way of eating but this doesn't mean it will be right for everyone.
1Kumar, S. & Kaur, G. (2013). Intermittent fasting dietary restriction regimen negatively influences reproduction in young rats: A study of hypothalamo-hypophysial-gonadal Axis. PLoS One 8(1). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3558496/
2Olson, B.R., Cartledge, T., Sebring, N., Defensor, R., & Nieman, L. (1995). Short-term fasting affects luteinizing hormone secretory dynamics but not reproductive function in normal-weight sedentary women. The Journal of Clinical Endocrinology & Metabolism, 80(4). Retrieved from https://academic.oup.com/jcem/article-abstract/80/4/1187/2650029?redirectedFrom=fulltext
3Wolfram, T. (2018). Investigating intermittent fasting. Retrieved from https://foodandnutrition.org/from-the-magazine/investigating-intermittent-fasting/
4Sharp, A. (2018). Intermittent fasting for weight loss - the evidence based pros & cons. Retrieved from https://www.abbeyskitchen.com/intermittent-fasting-weight-loss-evidence-based-pros-cons/?fbclid=IwAR3lrQO3naYc29eGVQMhcZc5TiWEzixgkTLUD8isvL7ZH_W7QSB5Tg6Xh4I
5Harvie, M. & Howell, A. (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(1). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5371748/
6Gabel, K., Hoddy, K., Haggerty, N., Song, J., Kroeger, C.M., Trepanowski, J.F., Panda, S., & Varady, K. (2018). Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutrition and Healthy Aging 4(4). Retrieved from https://content.iospress.com/articles/nutrition-and-healthy-aging/nha170036
7Orenstein, B. (2014). Intermittent fasting: The key to long-term weight loss? Retrieved from https://www.todaysdietitian.com/newarchives/120914p40.shtml
8Hill, J.O., Schlundt, D.G., Sbrocco, T., Sharp, T., Pope-Cordle, J., Stetson, B., Kaler, M., & Heim, C. (1989). Evaluation of an alternating-calorie diet with and without exercise in the treatment of obesity. American Journal of Clinical Nutrition, 50(2). Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/2667313/
9Laessle, R.G., Platte, P. Schweiger, U., & Pirke, K.M. (1996). Biological and psychological correlates of intermittent dieting behavior in young women. A model for bulimia nervosa. Physiology & Behavior 60(1). Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/8804634/