Fasting is one of the most ancient healing traditions in the world, and is practiced by nearly every culture on earth. Hippocrates, the father of modern medicine, prescribed fasting as a treatment for illness, and ancient Greeks suggested it not only to treat illnesses, but also to improve cognitive abilities. Fasting also is widely used for spiritual purposes, and is part of virtually every religion in the world. In modern times, however, fasting has been on the decline. We have such a regular and consistent supply of food that most Americans are eating throughout the day every day. However, the ever-popular desire to lose weight or just live healthier has led to a growing popularity in what’s known as intermittent fasting, which can lead to weight loss, improved mental clarity and can help with managing diabetes.
Blount Memorial registered dietitian Angie Tillman says while fasting is simply the absence of eating, intermittent fasting is a little more complex. “Technically speaking, we all fast for periods of time each day,” she said. “The word ‘breakfast,’ for instance literally means to ‘break the fast’ from not eating overnight. Intermittent fasting is not a diet. It’s more like an eating pattern. By deliberately fasting and then feasting, you generally wind up consuming most of your calories during a specific window of the day. You also wind up not eating for a larger window of time. The most important thing to remember about fasting, though, is that it’s not about calorie reduction; it’s about lowering insulin and switching the body’s fuel source so we’re burning fat for energy,” she explained.
“There are three types of intermittent fasting: 24-hour fasting, extended fasting and time-restricted fasting,” Tillman continued. “Time-restricted fasting is the most practical and easiest place to start because it simply narrows your eating window each day. Eating only between the hours of 11 a.m. and 7 p.m., for instance, would be considered time-restricted fasting,” she said.
Fasting, though, can have its ups and downs. “Like any change in our daily habits, intermittent fasting has pros and cons,” Tillman said. “On the plus side, it can promote weight loss, and it may improve mental alertness overall. If you have diabetes, it can improve insulin resistance and blood glucose control. It’s also totally free and very easy to begin doing. It’s flexible, too, because you can always adjust your hours of eating and fasting,” she explained. “However, intermittent fasting isn’t for everyone, and is definitely not recommended for people under age 18, people who have a history of eating disorders, those who are underweight, or pregnant or breastfeeding women. People also can experience hunger and a decrease in overall energy, particularly when they begin intermittent fasting. It’s also really important to watch what you’re eating during the time of day you’re eating. You want to avoid bingeing, and stay away from highly processed, low-nutrient foods,” she said. “If you have any medical issues, particularly diabetes, you’ll want to consult your physician before intermittent fasting so you know how it can affect you,” she added.
“The bottom line is that intermittent fasting is just one tool in a big toolbox,” Tillman continued. “It’s just one of many strategies that can improve our overall health and can help with managing weight,” she added.