Intermittent Fasting for Weight Loss: Pros and Cons for People With Diabetes

Abstract

Intermittent fasting encompasses various diets that cycle between periods of fasting and nonfasting; these diets don’t necessarily specify what to eat but when to eat. They range from fasting for whole days at a time to fasting for a matter of hours during the day. Historically, fasting was inevitable in times when food was not readily available, and many religious philosophies have practiced fasting for centuries; however, cyclically restricting or reducing calories has recently taken off as a popular way to lose weight and improve health outcomes. Although preliminary research shows intermittent fasting may be as effective for weight loss as continuous caloric restriction, more research is needed to determine the long-term effects of intermittent fasting on other pertinent diabetes clinical outcomes. Intermittent fasting is generally grouped into two main categories: whole-day fasting and time-restricted feeding. Both categories range in flexibility of time spent fasting. Whole-day fasting includes regular 24-hour time periods of fasting; the strictest form is alternate-day fasting where 24 hours of fasting are followed by 24 hours of nonfasting continuously. Less strict but similar is the alternate-day modified fasting in which fasting days are allowed the limited consumption of 500 to 600 calories. Probably the most popular type of whole-day fasting is 5:2, 5 days of nonfasting followed by 2 days of fasting or modified fasting allowing 500 to 600 calories. Instead of restricting full days of eating, time-restricted feeding involves fasting during specified hours of the day. Perhaps the most popular type of time-restricted feeding is 16:8, 16 hours of fasting followed by an 8-hour time period of nonfasting. More flexible and strict time restrictions exist such as 12:12 (12 hours fasting, 12 hours nonfasting) and eating 1 meal per day (about 23 hours of fasting). Generally, the idea behind intermittent fasting is to reduce total amount of calories consumed to lose excess weight and benefit from positive health benefits that may come along with weight loss. Intermittent Fasting for Weight Loss: Pros and Cons for People With Diabetes