18 I Summer 2019 www.anjc.info CHIRO ASSIST TECHNIQUE Council NUTRITION Council NUTRITION OUR HEALTH REHAB Council FASTING Considerations By Dr. Julianne Monica Chair, ANJC Nutrition Education Council How many of your patients have asked you about the benefits of fasting? It is being touted as having anti-aging effects, facilitating fat loss, elevating mood and providing mental clarity and boosting cognition. Research supports the use of intermittent fasting for potential prevention and treatment of cardiometabolic disorders. The term intermittent fasting is defined as intermittent energy restriction, or intermittent calorie restriction, diet plans that cycle between a period of fasting and non-fasting over a defined period. In 2013, Mosley & Spencer published a best-selling book titled “The FastDiet” which describes the benefits of severely restricting energy intake for two days a week but eating normally during the rest of the week. This was a big push for this popular concept. In 2016, an internet search using the terms “intermittent/diet-fasting” had more than 210,000 hits. In contrast, there is a shortage of evidence-based support for intermittent fasting that can be used to generate recommendations for public health practices. The bulk of scientific evidence for the health benefits of intermittent fasting primarily comes from studies of male rodent models. Human studies have largely been limited to observational studies of religious fasting (e.g. during Ramadan) and experimental studies with modest sample sizes. In randomized, intervention trials studied thus far, the efficacy of intermit- tent fasting on human health supports weight loss. Data is lacking regarding the impacts of intermittent fasting on other health behaviors such as diet, sleep, and physical activity. It’s typically assumed that pre-ag- ricultural humans and our hominid ancestors experienced long periods of famine, or, at the very least, weren’t grazing and snacking all day. It’s more likely that they feasted and fasted, going some length of time between successful hunts. Today, this would be called alternate day fasting. It has alternating fasting days, during which no calories are consumed, and feeding days, during which foods and beverages are consumed freely. This fasting regimen was as effective as simple daily caloric restriction in reducing obesity-associated body weight and fasting insulin and glucose concentrations. Alternate-day fasting in rodent models of obesity has also been shown to reduce total plasma choles- terol and triglyceride concentrations, reduce liver steatosis and inflammatory gene expression and have beneficial effects on cancer risk factors, such as cell proliferation. Other considerations for these study purposes and the practice in general is hunger and mental status, as well as post-fast energy intake/calories which can offset the positive effects and are important outcomes to consider with extended fasting during waking hours. In a recently reported study, 16 women did a two-day fast resulting in distraction, but not hunger, and was associated with a low mood and perceived work performance compared with two days prior to and following the fasting period. The sparse data on alternate-day fasting suggest that this regimen can result in modest weight loss and lead to improvements in some metabolic parameters. However, reports of extreme hunger while fasting indicate that this may not be a feasible public health intervention. Modified fasting regimens may be tolerated a bit better. They generally specify that energy consumption is limited to 20–25% of energy needs on regularly scheduled fasting days. The term fasting is used to describe periods of severely limited energy intake rather than no energy intake. This type of regimen, also called intermittent energy restriction, is the basis for the popular 5:2 diet which involves energy restriction for two non-consecutive days per week and unrestricted eating during the other five days of the week The outcome here was decreased visceral fat, leptin, and resistin, and increases in adiponectin. Similar studies conducted by this research group also found that in mice these fasting regimens appear to reduce adipocyte size, cell proliferation, and levels of insulin-like growth factor 1. Time restricted feeding that had daily fasting intervals ranging from 12 to 21 hours in numerous rodent models were