The Pros & Cons of Intermittent Fasting

By Molly O'Brien

The practice of fasting has been used for centuries in many religions to create spiritual discipline. In recent years, the health and fitness community in the West has adopted fasting as a tool for weight loss as well as a form of spiritual enlightenment. Intermittent fasting (IF) is a term used to describe an eating pattern consisting of a period of no food intake followed by normal eating. The general idea is to monitor when you eat, not necessarily what you eat. Surprisingly, many benefits accompany fasting apart from weight loss. However, there is a physiological cost as well.

Health Benefits

The most obvious benefit of fasting is weight loss. According to a study in the International Journal of Obesity, intermittent fasting reduces calorie consumption, stimulates fat burning hormones and increases overall metabolic rate. Other studies have found that intermittent fasting lowers blood sugar levels by 3–6 percent and results in heightened insulin sensitivity. There are cardiac benefits, too, as fasting lowers cholesterol and triglyceride levels in the blood, thereby reducing the risk of heart disease. Finally, a study in the Journal of Molecular Science showed that intermittent fasting increases the production of brain hormones that are linked to nerve cell regrowth, reducing the risk of memory deficits in older people and enhancing the recovery of nerve cells in certain neurodegenerative disorders.


While intermittent fasting appears to have potential benefits, researchers have been unable to determine who will benefit most in terms of gender and age. Some studies show conflicting results, and long-term effects have not yet been studied. In addition, fasting has certain physiological and psychological effects that may prove troublesome: hunger, dizziness, fatigue, poor concentration and potential for eating disorder development.

Common Fasting Practices

The 16/8 Method (aka Leangains Protocol) involves fasting for 16 hours and feeding for eight hours. People typically fast from 8 p.m. to noon of the following day and then eat regularly from noon to 8 p.m.

The Eat-Stop-Eat Method involves abstaining from all calorie containing foods for a 24-hour period, once or twice a week.

The 5:2 diet involves five days of non-restricted eating and two days of minimal caloric intake: 500 calories for women and 600 calories for men.

Molly O'Brien is a freelance writer based in Gainesville, Florida. She specializes in community and personal health topics. Born in Huntington, New York, she graduated from SUNY Farmingdale with a Bachelor of Science in biology. Molly has a passion for literature, language and art in all forms. She plans to pursue a master’s degree in English with a specialization in creative writing.