Fasting: Fact Or Fiction?
Fasting for fat loss: it’s another nutrition hot-topic that gets simultaneous flack and praise. Some people swear by fasting while others swear it only helps them gain weight. Subjective opinions aside, let’s take a look at the truth behind the phenomenon. Is fasting a fact or is it fiction?
What Is Fasting?
In order to weigh the pros and cons of fasting, we must first understand what it really is. Fasting refers to a period of time in which an individual eats very little to no calories. The time one spends in a fasted state can range from a few hours to a few weeks. Often times, fasting is performed for religious purposes. This article, however, will focus on routine fasting as a means for fat loss.
Types of Fasting
The most common word to precede fasting is intermittent. Intermittent fasting, though all the rage, is actually an umbrella term that covers many types of fasting. The word ‘intermittent’ simply means occurring periodically. There is no set of rules for intermittent fasting, but rather a set of subcategories. Three common subcategories include: time restricted feeding, alternate day fasting, and the 5:2 diet.
- Time restricted feeding refers to a 16 hour fasting period followed by an 8 hour feeding period. Within these eight hours, individuals can eat whatever they want without feeling the pressure of tracking their food intake. But, because the individual is fasting for the other 16 hours of the day, they should theoretically still be in a caloric deficit.
- Alternate day fasting is just as it sounds: one day of eating alternated with one day of fasting. When fasting, individuals may eat up to 25% of their usual caloric intake, or about 500 calories. When feeding, individuals are open to eating whatever they want. The idea behind alternate day fasting is that you only have to restrict what you are eating half of the time.
- The 5:2 diet is also as it sounds: five days of feeding followed by two days of fasting. Generally, females can allow for up to 500 calories on a day of fasting, and males can allow for up to 600. These calories should come from high fiber, high protein sources. This type of fasting, like others, is meant to promote a net caloric deficit, meaning the amount of calories consumed over one week is less than it previously was. Unlike other methods, the 5:2 diet focuses on making quality food choices throughout the week of feeding.
- Prolonged fasting refers to a fasting period lasting anywhere from three days up to three weeks. This is an incredibly severe form of fasting and an individual should undoubtedly consult with their physician before putting this method into practice.
Advantages of Fasting
Every method of fasting has the same overarching goal: caloric restriction accompanied by weight loss. While some modes are more severe than others, fasting is meant to promote a feeling of control. If an individual makes healthy choices during feeding AND strictly adheres to their fasting schedule, chances are they will see significant weight loss.
While hunger is a concern, especially when starting out, it normally subsides by week eight. Fasting correctly can increase fat free mass and improve glucose and insulin levels.
Disadvantages Of Fasting
Fasting of any sort is not a simple feat. While the weight loss and biomarkers may seem appealing, it must be noted that these results are not superior to a typical caloric restriction. Reducing your daily caloric intake without fasting will also increase weight loss and improve glucose and insulin levels.
While fasting is intended to promote weight loss, it is possible for an individual to binge eat during their feeding period so much so that their total calories stay the same. Thus, no change in weight would occur. While fasting can lead to weight loss, it can also disrupt sleep cycles, increase hunger, and affect your mood. Energy levels can also be depleted, which is important to consider, especially if you exercise.
Who Should Fast?
While fasting may promote dietary adherence, it certainly comes with its disadvantages. Fasting can increase fat loss, but if macronutrients (protein, fat, and carbs) are ignored, muscle loss may also occur.
If you are a regular exerciser, it is important to know that physical exertion in a fasted state can cause the body to use protein as energy and therefore diminish muscular gains. Before you start fasting, consider the pros and cons, as well as feasibility. As a safety precaution, always consult your doctor before starting an extreme dieting method.
Works Cited
Rynders, Corey A, et al. “Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss.” Nutrients, MDPI, 14 Oct. 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6836017/.
