By Erika Bettermann, master’s nutrition student, Coordinated Program
Many of us have heard the saying, “Well, that’s how the cavemen did it!” when it comes to eating patterns and the types of foods we consume. It may sound cliché, but there is a twinge of truth to it. Before there were reliable food sources, our bodies adapted to allow us to survive during food scarcity. Today, however, we have food at our fingertips at nearly all hours of the day (We’re looking at you, delicious bag of potato chips just waiting to be peeled open!). These snacks are often consumed in the late hours of the evening when we finally wind down from a busy day and are ready to indulge in our latest guilty-pleasure Netflix binge. Unfortunately, these late-night snacking habits can lead to a higher risk of obesity or diabetes.
So what does this have to do with those cavemen?
When we eat a meal, the carbohydrates are broken down into individual sugar molecules that are used first and foremost for energy. For our bodies to use that sugar, it secretes the hormone insulin, which allows the sugar to enter our cells. However, if we eat more carbohydrates than our bodies need, the sugar is converted to fat. In between meals, when we are not consuming any food, there is no sugar in the blood to be taken up by cells, so insulin levels fall. At this point, our bodies start using stored fat for energy. To sum it up, when those cavemen did not eat for hours on end, their bodies would burn fat for energy because sugar was not available.
What does all of this mean for me?
Great question! The idea of intermittent fasting (IF) has been around for decades, but was popularized in 2012 by the BBC TV documentary, Eat Fast, Live Longer. IF restricts when we eat during the day to a shorter window of time (for example, instead of eating from 7 AM to 7 PM, you can only eat from 7 AM to 3 PM). The idea is to give our bodies more time to burn fat, rather than carbohydrates, for fuel, improve our metabolism, and yes, allow us to shed a few pounds!
But that sounds hard – I get hungry in the evening!
I hear you! Fortunately, a 2017 study by Byrne and colleagues showed that an alternative to IF exists that may be more realistic and just as efficient. Byrne studied the effects of intermittent energy restriction, which consists of periods of caloric restriction interspersed with periods of normal energy intake, and continuous energy restriction, characterized by a constant daily energy restriction for a certain period. He found that the participants who alternated between two weeks of a restricted diet and two weeks of a normal energy intake had a greater weight loss and fat loss than participants whose caloric intake was restricted throughout the entire study. Furthermore, six months after the study, the intermittent participants gained back less weight than the participants with constant energy restriction. Ultimately, intermittent energy restriction can result in higher energy expenditure, or how many calories we burn when resting, compared to constant restriction.
Bottom Line
Intermittent fasting has been proven useful in weight loss and fat loss; however, it may not be the easiest method. Intermittent energy restriction, which allows food consumption in smaller quantities with no time restriction, might be the realistic ticket to weight loss that keeps us burning more calories all day long. The bottom line is that intermittent fasting does not provide us with a magical superpower. The trick is to break up energy restriction with periods of normal energy intake to increase our energy expenditure, which will allow us to burn more calories and shed those pesky pounds.