A Guide to Intermittent Fasting

By Jennifer Engels, MD

For a host of reasons – spiritual, emotional and physical – humans have engaged in fasting for thousands of years, and in recent years the practice has been given new life through what is called intermittent fasting (IF). People are using IF to lose weight, improve their health and simplify their lifestyles, and it’s currently one of the world’s most popular health and fitness trends.

To provide some context, the idea of fasting as a tool for promoting health really goes back to the origin of our species. Our ancient ancestors’ hunter-gatherer lifestyle produced periods of bounty, followed by periods of very limited caloric intake. Consequently, the human body evolved to cope with an uncertain food supply and actually developed the means to thrive during times of food scarcity.

Today, however, our largely sedentary lifestyle, combined with access to high-calorie foods, often highly processed and packed with sodium and sugar, have interrupted the natural processes that evolved over millennia to keep us alive. And modern research suggests that our constant access to calorie-rich foods might well be responsible for the explosion in obesity rates and other health issues we’ve seen in the last half century or so.

Hence, getting back to a more natural ebb and flow of calories in the diet might well help individuals deal with a multitude of health problems, such as obesity, diabetes, high blood pressure and high cholesterol, to name a few. And that brings us to IF as one way of providing that help.

Definition of Intermittent Fasting

Stated in its simplest terms, IF involves eating nothing, or very few calories, for a certain period of time and then eating as usual for another set period. IF can take several forms including:

• Alternative-day fasting – This is a somewhat extreme form of IF as it involves a total fast from food every other day, two or three days a week. 

• 5:2 fasting – The 5:2 approach is a slightly less demanding form of IF in which you eat normally five days a week but cut your calories to 500 a day for women and 600 for men on two non-consecutive days of the week, such as Tuesday and Thursday. 

• Time-restricted fasting – This form of IF involves eating all your meals within a set, restricted time each day. An example of this approach to IF is 16:8 fasting in which you consume all your meals in an 8-hour time span and fast for the remaining 16 hours of the day. Many find the 16:8 method to be the simplest and most sustainable form of fasting, making it the most popular method.

Water Fasting

This is still another variant of IF, and during a water fast you consume nothing but water. A water fast can last from 24 up to 72 hours, but you should not engage in water fasting for longer periods unless you’re under strict medical supervision.

One of the leading proponents of water fasting is Dr. Jason Fung, a Canadian nephrologist and author of the books The Obesity Code and The Complete Guide to Fasting.

Based on his experiences with patients, Fung concluded that IF is an extremely effective way to lower insulin levels in the body and lose weight. Insulin, a hormone made in the pancreas, helps the body use sugar for energy, and prolonged periods of low insulin force the body to turn to stored sugar as a fuel source, and when that has been depleted, the body must burn fat.

In addition, Fung concluded that exercise is an extremely inefficient way to lose weight. While exercise certainly has its health benefits, he says, “If I had to guess, diet is 95% of the battle and exercise is 5% of the battle.”

Technically, true water fasting involves consuming only water for a given period of time, but Fung is willing to bend the rules a little, permitting consumption of tea and coffee, even coffee with a bit of cream, during fasting periods. But he believes that to achieve the maximum benefits from water fasting, you should consume only water while fasting.

Fasting Mimicking

Another approach to intermittent fasting and weight loss, fasting mimicking tricks the body into thinking its fasting, even though you’re eating food.

The basic idea behind fasting mimicking is that while there is solid scientific evidence supporting fasting, it can be difficult to completely forgo food and even more challenging to fast long enough to derive any real benefits from it. And those difficulties and challenges led to the emergence of fasting mimicking.

The goal of fasting mimicking is to find a “sweet spot” between consuming too much and too little food, and the individual behind its development is Dr. Valter Longo. A cell biologist at the University of Southern California, Longo has conducted extensive research into food restriction and how it may affect our health and longevity.

The ProLon Fasting Mimicking Diet

Based on his research, Longo developed the ProLon Fasting Mimicking Diet to help individuals get into the fasting mimicking program and its health benefits.

Briefly stated, this is a reduced-calorie diet with a specific macro- and micronutrient composition that makes your body think it’s fasting while you’re actually consuming reduced amounts of food.

The fasting mimicking diet lasts five days and works as follows:

• Day 1 – You consume 1,100 calories, 11% protein, 46% fat, and 43% carbohydrate. 

• Days 2-5 – You consume 725 calories per day, 9% protein, 44% fat and 46% carbohydrate.

During these five days you should also consume a minimum of 70 ounces of water per day, while avoiding caffeine.

To achieve optimal results, the five-day fast cycle should be repeated once per month for a minimum of three months.

Though anyone can follow the principles of fasting mimicking and do it on their own, the ProLon Fasting Mimicking Diet features a meal program available at WeCare Integrative Medicine. It consists of a pre-packaged meal kit of plant-based whole foods that does not include any meat or dairy foods, gluten, GMO or processed foods. It also contains a supplemental energy drink and a plant-based omega-3 supplement.

A Simple Four-step Beginning

If this information on intermittent fasting interests you, but you’re not quite sure how to begin, here’s a simple, self-help method you might use as a starting point.

1. Avoid sugars and refined grains. Instead eat fruits, vegetables, beans, lentils, whole grains, lean proteins and healthy fats, essentially a plant-based, Mediterranean-style diet. 

2. Let your body burn fat between meals. This means not snacking and being as active as much as possible during the day. At a minimum, get up from your computer and move around for a few minutes several times a day. 

3. Try a simple form of intermittent fasting. You can do this by limiting the hours of the day when you eat, like eating all meals between 7:00 AM and 3:00 PM or 10:00 AM and 6:00 PM. 

4. Don’t eat a meal or snack at bedtime, ever!

Help Available at WeCare Integrative Medicine

Beyond self-help, medically-directed assistance and support are available for you at WeCare Integrative Medicine in Frisco. Functional Nutrition and Life Style Coaching are among my specialties, and I encourage you to contact our clinic to schedule your initial consultation, and give me the opportunity to guide you through a program that is realistic and sustainable for you.