By Dr. Kathleen Mahannah, ND
Intermittent fasting (IF) is a lifestyle or dietary approach that has gained more attention recently, and rightly so. Studies are demonstrating promising health benefits of IF, including: weight loss, reduction in cardiovascular risk factors, enhanced cognition, better mood, and hormone balance. Intermittent fasting alternates periods of normal food intake with extended periods (usually 16–48 h) of low-to-no food intake. This approach can take various forms, such as:
- Feeding Window: You can only eat during a set period of time every day (from 10 a.m. to 6 p.m, for instance, which is a 14 hour fast).
- Alternate-Day Fasting: This diet can take different forms: you can eat over 12 hours then fast for 36 hours; you can eat over 24 hours then fast for 24 hours; or you can eat normally over 24 hours then eat very little (about 500 kcal) over the next 24 hours.
- Eat-Stop-Eat: You fast or restrict calories for 24 hours, either at regular intervals (two days per week in the 5:2 Diet) or just from time to time.
- Random Meal Skipping: You skip meals at random throughout the week.
During fasting, the body switches over to using fat as its fuel source; this is what helps to support fat loss during intermittent fasting. Further, it appears that IF helps improve cellular repair, metabolism and rejuvenation.
Benefits of Intermittent Fasting:
- Supports weight loss: During fasting, the body switches over to using fat as a source of fuel. Studies on humans who used IF for 8-12 weeks lost anywhere from 2.5-8% of their body weight (that’s up to 14lbs. in someone who weighs 170lbs.)
- Reduces cardiovascular risk factors: Studies indicate that IF can reduce cholesterol, blood pressure, weight, and inflammation (measured by C Reactive Protein) which are all associated with risk of cardiovascular disease. Other studies demonstrate that people who fast have a lower chance of being diagnosed with diabetes.
- Improve cognition: Animal studies have indicated that intermittent fasting can reduce the risk of atherosclerosis, metabolic dysfunction, and cognitive dysfunction over the life span.
- Improve hormone balance in women with Polycystic Ovarian Syndrome (PCOS): Women with this condition who use IF can benefit from normalization of the menstrual cycle, improved metabolism and weight loss.
- Support mood during perimenopause: IF can be one part of the puzzle in supporting women suffering from perimenopausal depression and/or anxiety.
Keep in mind that IF is not for everyone. People with impaired glycemic control should speak to their Naturopathic Physician or GP before giving it a try. Also, if you’re pregnant, underweight, younger than 18, or have a history of disordered eating, IF is probably not for you.
How to get started:
First, speak to your ND or GP to see if intermittent fasting is an option for you. If it is, pick an IF routine that works best for your schedule and routine. If you choose the ‘feeding window’ routine, start with a 14-hour overnight fast (ex. from 8pm to 12pm). Try using an app like ‘Zero’ to help keep you on track and watch your progress over time. During the feeding window, eat as you normally do. Studies show that in fact, people do NOT tend to ‘eat more’ during the feeding window. If you’d like some guidance as to what is best to focus on eating when you’re not fasting, speak to your Naturopathic Physician for guidance.
Learn more about Dr. Kathleen on her website (www.drkathleenmahannah.com), connect with her on Instagram (@dr.kathleenmahannah) or find her at Innovative Fitness North Vancouver on Wednesdays and Fridays!
Nair, P., & Khawale, P. (2016). Role of therapeutic fasting in womens health: An overview. Journal of Mid-life Health,7(2), 61. doi:10.4103/0976-7800.185325
Horne, B. D., Muhlestein, J. B., & Anderson, J. L. (2015). Health effects of intermittent fasting: Hormesis or harm? A systematic review. The American Journal of Clinical Nutrition,102(2), 464-470. doi:10.3945/ajcn.115.109553