Intermittent Fasting: What’s the Hype?
In a world where wellness is ever-changing, and everyone is looking around the corner for new trends, intermittent fasting is surely one of them that is talked about and has been gaining traction over the last couple of years. So what exactly is intermittent fasting and can it help you reach your health and nutrition goals? In this article, we will dive into the research and explore the science behind intermittent fasting as well as review one of the more common methods of intermittent fasting.
Understanding Intermittent Fasting
If you are seeking to achieve weight loss, on a basic level you must not consume more than your daily calorie requirement and you must achieve and maintain a calorie deficit in order to sustain long-term weight loss. However, for some, caloric restriction alone may not be suitable for their lifestyle or align with their preferences which nudges them to look for alternative methods to attain a caloric restriction. Thus, intermittent fasting has become an alternative approach for weight loss for those who do not prefer to focus on the daily restriction of calories or who do not prefer to track calories/macronutrients. Instead of focusing on restricting calories, intermittent fasting restricts the time you are allowed to eat as well as being able to eat ‘normally’ on your set eating days/hours.
The Science Behind Intermittent Fasting
There are a few different types of intermittent fasting which include: alternate-day fasting, modified fasting, and time-restricted fasting. Each can vary in their approach as well as lengths of fasting. The basis behind intermittent fasting, specifically time-restricted fasting, suggests that reducing the allotted hours allowed to eat may have a subsequent effect of decreasing a person’s ability to overeat during the allowed eating hours. According to Dana Angelo White, MS, RD, ATC, “[intermittent fasting] is promoted as a potential plan for weight loss, increased longevity, improved brain function and mental clarity, and reduced risk of chronic disease.” White also references that other studies have found benefits with intermittent fasting and improved insulin resistance, regulation of our bodies' circadian clock, improvements in blood lipid levels as well as changes in our bodies metabolic ability to “switch between burning carbohydrates and fat as fuel” (Angelo White, MS, RD, ATC, 2021). Other researchers, Regmi and Heilbronn (2020) add that there has also been a correlation between time-restricted eating and improvements in triglycerides and inflammation. Regmi and Heilbronn also go on to say that our circadian clock is responsible for directing “behavior and metabolism such as hormonal signaling, body temperature, nutrient absorption, and metabolism.”
Implementing Intermittent Fasting
There are no set “guidelines” for intakes when implementing intermittent fasting and can vary depending on the approach you choose to take. If you are looking to implement intermittent fasting, you must first decide the amount of time you want to spend fasting as well as the amount of time you are allowed to eat. For each of the different fasting methods, the time spent “fasting” can vary widely. For example, in alternate-day fasting, you will fast every other day and typically only consume non-calorie foods such as coffee, water, or tea on these days.
In modified intermittent fasting, the most common approach is the 5:2 method in which you will fast for 2 non-consecutive days out of the week and then eat normally the other 5.
The other type of fasting is time-restricted fasting, which we focus more on in this post, you will fast for a certain amount of time during a 24-hour period and be allowed to eat normally for a set number of hours. For example, the most common approach is the 16:8 fast where you complete a majority of your 16-hour fast in the overnight/sleeping hours, and depending on preference, start your fast in the late afternoon or early evening.
When considering implementing intermittent fasting, it is important to discuss this with your Primary Care Provider. According to Angelo White (2021), there are a few conditions and diagnoses that fasting may not be recommended, such as “[p]eople with type 1 diabetes, those with type 2 diabetes who require insulin, individuals suffering from hypoglycemia, those taking medications that require consumption with food, and pregnant or breastfeeding women…” White also notes that individuals with an eating disorder or history of disordered eating should be cautious of implementing intermittent fasting.
Considerations of Intermittent Fasting
While intermittent fasting may seem like a win-win solution for weight loss, it is not without the possibility of downsides. For some, there is a possibility of unwanted side effects that may include: alterations in energy levels, extreme hunger, bloating, gas, headaches, light-headedness, or fatigue (Angelo White, MS, RD, ATC, 2021). Many of the studies regarding intermittent fasting have been completed on animals (such as mice) and a smaller amount of studies have been completed on humans. The research on the long-term effects of intermittent fasting continues to be ongoing.
Conclusion
For some, intermittent fasting may be a feasible option for implementing their weight loss journey. However, it should also be noted that this may also be a short-term option to initiate weight loss that may not always be a long-term change that is maintainable. As stated previously, it is recommended to discuss with your primary care provider before initiating intermittent fasting, and, to make sure adequate nutrition is being obtained, it is also important to consult with a Registered Dietitian. A Dietitian can help address any nutritional deficiencies that may occur and help implement behavior modification techniques for long-term success.
Sources:
Angelo White, MS, RD, ATC, Dana. “CPE Monthly: Intermittent Fasting — an Evidence-Based Assessment - Today’s Dietitian Magazine.” Www.todaysdietitian.com, Today’s Dietitian, June 2021, www.todaysdietitian.com/newarchives/JJ21p46.shtml. Accessed 24 Apr. 2024.
Medicine, Good Food Is Good. “Intermittent Fasting: Benefits, How It Works, and Is It Right for You?” Good-Food, 4 Feb. 2022, health.ucdavis.edu/blog/good-food/intermittent-fasting-benefits-how-it-works-and-is-it-right-for-you/2022/02.
Patterson, Ruth E., et al. “Intermittent Fasting and Human Metabolic Health.” Journal of the Academy of Nutrition and Dietetics, vol. 115, no. 8, Aug. 2015, pp. 1203–1212, www.ncbi.nlm.nih.gov/pmc/articles/PMC4516560/, https://doi.org/10.1016/j.jand.2015.02.018.
Regmi, Prashant, and Leonie K. Heilbronn. “Time-Restricted Eating: Benefits, Mechanisms, and Challenges in Translation.” IScience, vol. 23, no. 6, June 2020, p. 101161, https://doi.org/10.1016/j.isci.2020.101161.
