16/8 Intermittent Fasting

Around the world, fasting has been and is still utilized as a cultural tradition, as an integral part of a religion, or as a component of medical therapy. Today, the practice of intermittent fasting as a means of losing weight or improving health has become popular in recent years. If you’re not familiar what intermittent fasting entails, it simply means that you consume food for a specific period of time during each day (or week) and fast the remainder of time. You can, of course (and should), drink non-caloric beverages such as water, tea, or coffee, as these keep you hydrated and help control appetite. The goals of this type of fasting are (1) reduce overall caloric intake and/or (2) induce a state of ketosis in the body so stored fat is used to generate energy.

A few of the more popular intermittent fasting methods include:

• Alternate-day fasting: you eat as you normally would one day, and then completely fast or eat only a small meal (fewer than 500 calories) the next day.
• 5:2 fasting: you eat your normal diet 5 days of the week, and then fast 2 days of the week.
• Time-restricted fasting: you eat your normal diet within a certain time period and fast the other hours; this typically involves eating 2 meals daily.

How does 16/8 intermittent fasting work?

16/8 intermittent fasting involves an eating window of 8 hours, usually 2 meals or 1 meal plus snacks, and an abstinence window of 16 hours. Drinking non-caloric beverages is encouraged throughout the waking hours. This eat/fast cycle can be part of your daily routine or less frequent—once, twice per week, or every other day—whatever suits your personal needs.

The popularity of 16/8 intermittent fasting has grown for some notable reasons. In general, dieters consider it to be more flexible than other diets; the “rules” aren’t set in stone as many other restrictive diets are. 16/8 intermittent fasting is simple to follow and fits quite easily in today’s otherwise hectic lifestyles. Some people find that their busy schedules really only allow for 2 quality meals per day, or 1 large meal plus a few healthy snacks.

What are the purported health benefits of intermittent fasting?
First, intermittent fasting, and following a regimen such as 16/8, will by virtue of its design, reduce your calorie intake. Calorie restriction in turn, may contribute to weight loss, which is the reason most people are intrigued by intermittent fasting.  Of course, that’s assuming that you aren’t gorging yourself during the 8-hour eating window. Consuming too many calories may lead to weight gain over time, not to mention gastrointestinal discomfort.

Second, some research has shown that intermittent fasting helps improve blood sugar control; this may theoretically decrease the risk of type 2 diabetes, or be included as a non-medical, complementary management strategy.[i] Third, a few animal studies have shown an increase in longevity, but evidence of this in humans remains limited.[ii] Still, a reasonable lowering of your caloric consumption to lose excess weight can improve your metabolic functions and promote overall health. This itself, may help increase longevity, preserve mobility, and improve vitality.

How do I get started with intermittent fasting?
Since the 16/8 regimen is relatively simple, you first must choose an 8-hour window that works best for you and syncs up with your lifestyle (including your work schedule), whether you’re an early riser or a night owl or somewhere in between. An initial consideration is whether you start your day with breakfast, or skip it. If you normally eat breakfast, then your 16/8 window might be 7:00am to 3:00pm or 9:00am to 5:00pm. If you normally skip breakfast, then your window might be 12:00pm to 8:00pm or 2:00pm to 10:00pm.

Here’s how it would work for the breakfast lovers with an eating window of between 9:00am to 5:00pm: you’d fast overnight; eat a decent breakfast around 9:00am; eat lunch as your main meal between noon and 12:30pm; and eat a very light dinner (or snack) around 4:30pm and finish up by 5:00pm. For the breakfast skippers with an eating window of between noon and 8:00pm: you’d eat a healthy lunch around noon; eat dinner any time before 7:30pm, plus any snacks during the day; and end the day by starting your evening/overnight fast.

There’s only a 3-hour difference in the start and stop times of these 2 fasting strategies. This can make all the difference when it comes to which time frame is more conducive to your lifestyle. Of course you can tweak these a bit, or change them up from week to week if you choose. Just remember that the overall goal is to make healthy food and beverage choices that support healthy weight loss. It takes effort on your part to follow a 16/8 intermittent fasting program. Don’t negate it by eating processed food, fast food, or junk food.

Is intermittent fasting safe?
For the average person who is relatively healthy and doesn’t have any chronic conditions, the answer is “probably yes.” That being said, it’s not everyone’s cup of tea, as some people find it difficult to overcome the unpleasant side effects—hunger, headaches, nausea, fatigue, or insomnia—caused by skipping meals. These side effects are usually only temporary.

Women who are pregnant, trying to conceive, or breastfeeding, or have a medical condition such as diabetes, gastroesophageal reflux (GERD), kidney stones, low blood pressure, or something else, should consult their primary care physician before starting a fasting program of any kind. Keep in mind that extreme calorie restriction, as part of your fasting regimen, can lead to malnutrition. Individuals with a history of eating disorders, should exercise caution and seek medical advice.

What are the weight loss alternatives to intermittent fasting?
The long-term benefits of intermittent fasting aren’t definitive at this point. If you find it difficult to stick with a fasting regimen, you may find it easier or more tolerable to lose weight the “old-fashioned way.” Experts agree that the optimal weight loss strategy is to adopt healthy nutrition and enjoyable (fun) exercise habits. Gradually replace your “bad” habits with “good” habits, and you’ll be much more likely to stick with them. The longer you practice healthy habits, the longer you’ll reap the benefits. Also, it cannot be understated that good nutrition, such as what is included in the Mediterranean diet—is imperative to any form of fasting.

Consult with your physician before starting this or any exercise or nutrition program. You should not practice Intermittent Fasting if you are pregnant or nursing, under the age of 18, have type 1 diabetes and take insulin, are underweight, or have suffered from an eating disorder.

[i] Albosta M, Bakke J. Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Clin Diabetes Endocrinol. 2021;7(1):3.

[ii] Hwangbo DS, Lee HY, Abozaid LS, Min KJ. Mechanisms of Lifespan Regulation by Calorie Restriction and Intermittent Fasting in Model Organisms. Nutrients. 2020 Apr 24;12(4):1194.