Intermittent Fasting: Trend or Science?
* the opinions expressed are those of the author and not Nutrition Ink.
** Always consult with your primary care provider before starting any diet program.
Intermittent fasting seems to be the new health craze. Not only has is it a buzzword in the media, but it has become a popular topic among health professionals as well. So what is all the hype about, and is there any validity to it?
Intermittent fasting (IF) is a fancy term for the cycling between short periods of fasting and subsequent periods of eating. Also known as time-‐restricted eating, this method is often used to promote weight loss, as well as improving blood pressure and cholesterol. The most popular methods of IF include:
16 hour fast, 8 hour feeding window
12 hour fast, 12 hour feeding window
24 hour fast
Fasting in general has been around for centuries around the globe particularly in religious and ethnology practices. Our modern practices of IF come from the idea that we have moved away from the diet habits of our ancestors and towards a life of instant gratification, which in turn has effects on our overall health. The main idea was that as hunter-‐gatherers we stayed active most of the day with little food, and the body used stored fat for energy.
Most of the existing research on IF has been conducted with lab animals, but studies on humans are increasing. IF is hypothesized to help regulate metabolism through its effects on circadian rhythm (daily sleep/wake cycle), the gastrointestinal microbiome, and lifestyle behaviors (1). Disruptions in these systems can cause an increased risk of obesity, diabetes, cardiovascular disease, and cancer. According to one study done on mice, regulating intake of food to limited periods of time during the day can reprogram molecular energy metabolism and body weight regulation (1). At the moment, IF does not show any specific benefit over other low-‐calorie diet methods for weight loss (2). There are growing beliefs that IF can change the function of cells, genes and hormones, and reduce insulin resistance, oxidative stress and inflammation. Research is still inconclusive to prove the validity of these beliefs. There are worries that IF cause fatigue and lower performance as well as malnourishment and damaged immunity. However, there is little evidence so far that IF is harmful physically or mentally (2). It is safe to say that more human studies are needed on this topic, however the future of IF may look promising.
References: 1. Hatori M, Vollmers C, Zarrinpar A, et al. Time-‐restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-‐fat diet. Cell Metab. 2012;15(6):848–860. doi:10.1016/j.cmet.2012.04.0192.
2. Patterson RE, Laughlin GA, LaCroix AZ, et al. Intermittent Fasting and Human Metabolic Health. J Acad Nutr Diet. 2015;115(8):1203–1212.doi:10.1016/j.jand.2015.02.018
(Original image photographed and created by Mackenzie Campbell)