Fasting is not a new phenomenon. Many faiths recommend spiritual strengthening through periods of prayer and fasting—sometimes a day, sometimes seven, sometimes more. In the early 1900s scientists used fasting to treat diseases such as diabetes, obesity and epilepsy, although much of the published research was in laboratory animals. Recently, fasting—particularly intermittent fasting—is experiencing renewed interest as a medical treatment for disease rather than medication.
What is Intermittent Fasting?
Intermittent fasting is not a diet but rather a pattern of eating. It involves periods of eating and fasting. These cycles can be done every day or even one day a month. Two of the most popular types of intermittent fast are the 5:2 fast and the time restricted feeding fast.
The 5:2 fast, also known as The 5:2 Diet or The Fast Diet, calls for eating normally five days a week and restricting calories—500 calories per day for women and 600 calories per day for men—on the other two days. These fast days do not have to be right in a row.
Time-restricted feeding calls for eating food within a narrow window of time, typically a six to eight-hour window. Then fasting the remaining 16 to 18 hours a day. For example, with an eight-hour window, food is eaten between 11 AM to 7 PM. Research shows this type of fast is more manageable because most of the fasting period is overnight and into the morning.
Does Intermittent Fasting Work?
There is an emerging body of evidence that shows the benefits of intermittent fasting for type 2 diabetes and obesity are similar to those of a calorie restricted diet, but easier to follow. Research shows intermittent fasting is beneficial in reducing inflammation, lowering blood pressure, lowering heart rate, lowering cholesterol, and reducing insulin resistance.
A recently published study in February 2017 highlights the benefits of intermittent fasting. People in the study were separated into two groups. One group ate a regular diet. The second group followed a fasting-mimicking diet (FMD) consisting of 750 to 1,100 calories per day, for five consecutive days each month for three months. The FMD group was able to decrease body mass index, glucose, triglycerides, cholesterol, and C-reactive protein (a marker of inflammation). Moreover, those who were at risk of diabetes benefited more from the fast than participants who were not at risk.
Is Fasting Right for You?
If you take insulin or medications to control your blood glucose, intermittent fasting can increase your risk for hypoglycemia—low blood sugar. You may require a medication adjustment before going on a fast. As with any diet, you should first talk it over with your healthcare provider or diabetes health team to determine if intermittent fasting is right for you.
Intermittent fasting is not recommended for pregnant women, women who are breastfeeding, the elderly, individuals under the age of 20, people who are underweight and anyone with an eating disorder. Fasting may also not be good for people who take certain types of medications, such as beta-blockers.
Constance Brown-Riggs, MSEd, RD, CDE, CDN is a registered dietitian, certified diabetes educator, national speaker and author of The African American Guide to Living Well with Diabetes.. She is Dannon One Yogurt Every Day Nutrition Advisor.