The end of the celebratory eating season naturally invites a period of cleansing, fasting, and renewal. There are many ways to incorporate fasting into your new year’s cleanse – or intention to create a healthier lifestyle, including Hildegard’s, but there is also a method of fasting that might just offer a way to harness the health benefits of fasting without having to significantly modify your life around periods of prolonged fasting. This method is called intermittent or periodic fasting.
What is Periodic Fasting?
Periodic fasting is a fasting technique that involves choosing to consume your calories during specific periods of the day (or days of the week), while avoiding any calories for the balance of the day (or days of the week). The cycle between eating periods and fasting periods (i.e. intermittency) is repeated for prolonged periods of time – even as a permanent eating pattern.
The periods of time in which eating is allowed vary according to individual preferences, how people respond to the fast, and other lifestyle considerations.
Choosing longer or shorter periodic fasting windows
There are many different variations on the type of intermittent fast, but the primary differences have to do with the period of time allocated between eating and fasting and the dietary restrictions that may accompany the eating periods. There are other types of intermittent fasts, including a fasting window of up to 20 hours or a fasting window of a full 24-hour period, twice per week, known as the 5/2 fast.
While many of these variations offer similar benefits, the longer fasting windows often require a more disciplined approach to caloric intake as well as potential disruptions in physical activity levels.
The standard 8/16 (eat/fast) periodic fasting technique presumes an underlying diet that is generally healthy and nutritionally balanced, but does not require specific dietary restrictions. In other words, the benefits of this fasting technique are largely due to the timing of meals with lesser emphasis on the actual diet.
The most common and least intrusive intermittent fast involves a feeding period of 8-10 hours and a fasting period of 14-16 hours. Women tend to respond better to the shorter end of the fasting period, while men benefit from the slightly longer fasting period. This approach is a practical way to incorporate fasting without having to endure the discomfort hunger or modify activity levels due to caloric deprivation.
The ease of this method is largely due to the fact that the bulk of the fasting period occurs during sleep, with the balance being the waking hours of the morning and the resting hours of the evening.
If you regularly skip breakfast, you are likely already living a pattern that is quite close to an intermittent fast. In fact, the notion that “breakfast is the most important meal of the day” is the antithesis of the intermittent fast; skipping breakfast is the most effective way to achieve the 14-16 hour fasting period.
There is mounting research that the circadian rhythm of sleep is similarly present in terms of appetite, meaning our natural inclination to eat has peaks and troughs that are not biologically tied to the timing of our traditional three meals. This is particularly the case with breakfast; with some research indicating that one such trough in appetite occurs around 8 AM.
Speaking of sleep, getting 8 hours of sleep, skipping breakfast, and eliminating nighttime snacks will get you through the 8-10 hour fasting window. Conversely, the 8-10 hour feeding window is adequate to comfortably consume the calories and nutrition you need to function optimally.
Timing is Everything
Periodic fasting can be as simple as no food after 8 PM and lunch at noon the following day. If you tend to wake up hungry – or just happen to like breakfast, you can still maintain an intermittent fast by shifting the eating window earlier into the day and ceasing all eating by 4 PM.
The value derived from periodic fasting depends less on when the fasting and eating windows occur, than on the consistency of duration and timing of those windows.
The benefits of an intermittent fast come from the cyclical caloric intake, which conditions your body’s natural caloric optimization to utilize calories from food more efficiently. In simple terms, this means converting food directly into energy instead of fat, as well as recruiting fat stores for energy when in the fasting periods as opposed to relying almost entirely on glucose for energy, as is the case when we are eating almost constantly throughout the day.
Because this approach involves a myriad of hormonal responses, maintaining a consistent schedule is essential. Women are also more sensitive to these hormonal fluctuations than men, which is why the shorter fasting period is recommended. It is also why women should gradually incorporate the intermittent fast over a few weeks. Some women find that an intermittent fasting regimen that involves 3-4 days per week is adequate.
Adjusting your eating pattern
Intermittent fasting has been linked with many health benefits. In terms of indirect benefits, intermittent fasting tends to result in fewer overall calories consumed.
Limiting the hours of the day when food is consumed tends to also eliminate habitual snacking. Because the feeding window is limited, the meals are often closer together in time, which means the feeling of satiety is more likely to influence (reduce) the amount of food consumed in subsequent meals.
Further, it is not a “diet” but rather an eating pattern, thus the discipline is focused on time and not calories. While the benefits are optimized when eating whole, healthy, and nutritious meals, intermittent fasting can still be effective even when occasionally consuming less-than-ideal food sources, aka “cheat foods”.
The Health Benefits of Periodic Fasting
Health benefits associated with periodic fasting include decreased risk factors for diseases like diabetes, cardiovascular disease, and cancer. Previous research indicates fasting can have a beneficial effect on patients with diabetes and cardiovascular disease.
Intermittent fasting has also been shown to help reduce cholesterol levels in pre-diabetic people, affect the process of inflammation and even trigger positive immune response via stem cell regeneration.
Intermittent fasting has been linked to longevity and a reduction in neurodegenerative disorders like Alzheimer’s and Parkinson’s, though human research is still a long way from proving out the mechanisms of this relationship.
From a purely dietary perspective, intermittent fasting has been shown to promote weight loss and significant reductions in blood sugar and insulin levels, as well as a drastic increase in human growth hormone.
A modified way of life including activity
Incorporating an eating regimen that restricts calories or alters your eating pattern substantially should always be discussed with your healthcare practitioner, particularly if you have ongoing health concerns like diabetes. These fasting techniques are also unsuitable for children or the chronically ill.
The benefits of periodic fasting or other calorie restricting dietary plans are most pronounced when accompanied by regular, moderate physical activity.
Exercise will also keep your body keep from adjusting metabolically to the state of reduced caloric intake. This adjustment is part why many people hit those frustrating weight loss plateaus.
While the many benefits of intermittent fasting are far from guaranteed or even fully proven, the technique has a lot of potential, so if you are looking to jump-start your healthy new year, consider giving it a try to find out for yourself.