Many cultures and religions practice periods of fasting. In the Islamic tradition, the 9th month of the lunar calendar marks the beginning of Ramadan, which is characterized by a month-long fast in which Muslims do not eat from sunrise to sunset each day.
Now, only eating during nighttime hours might seem pretty extreme or even dangerous to some people, but in fact it appears that there might be health benefits to such a schedule of intermittent eating, or conversely, intermittent fasting. Some benefits might come from eating in a way that is more closely aligned with how our bodies might have evolved to eat. This ancestral approach would posit that as hunters and gatherers, we were probably more likely to eat a large meal after a hunt as opposed to eating smaller meals throughout the day. Some benefits might come from the caloric restriction that is often associated with fasting. There is evidence that caloric restriction can extend the lifespan of animals and can improve risk factors for disease (cholesterol, triglycerides) in humans.
In 2010, this review (free access) titled, “The impact of religious fasting on human health” was published in the Nutrition Journal. Here, the authors concluded that the findings regarding fasts and health have been mixed due to variations in the length of the fast, the percentage of people who smoke, take medications, or receive iv fluids, and the types of foods that are eaten during the fast (when eating is permitted). With regard to the types of foods consumed, the authors describe a “Daniel Fast” from the Christian tradition that involves avoiding animal products, refined carbohydrates, additives, preservatives, flavorings, sweeteners, caffeine, and alcohol. Therefore, the Daniel Fast somewhat controls for the types of food that are consumed and with the exception of the prohibition on animal products, it sounds similar to a paleo-style diet.
The bottom line is that the authors conclude that fasts often result in lower body mass, total cholesterol, LDL-C, and LDL-C/HDL-C ratio. Fasts such as the Daniel Fast have also been shown to lower blood pressure, blood lipids, insulin sensitivity, and biomarkers of oxidative stress.
So, keep in mind that you don’t have to be a card carrying member of an organization to practice intermittent fasting. Try skipping a breakfast or dinner one day. If you can’t imagine doing such a thing, try slowly working your way up to 12-16 hours (remember that you can count the hours that you are asleep) by starting with a few hours at a time and extending that time period one day a week.