What if I told you all you need to do to lose weight is read a calendar and tell time? These are the basics for successfully following an intermittent fasting diet.
Can it be that simple, though? Does it work? And what is the scientific basis for fasting? As a registered dietitian and expert in human nutrition and metabolism, I am frequently asked such questions.
Simply stated, intermittent fasting is defined by alternating set periods of fasting with periods in which eating is permitted. One method is alternate-day fasting. On “fast days,” followers of this form of fasting are restricted to consuming no more than 500 calories per day; on “feast days,” which occur every other day, they can eat freely, with no restrictions on the types or quantities of foods eaten.
Other methods include the increasingly popular 5:2 method. This form of fasting involves five days of feasting and two days of fasting per week.
Another variation relies on time-restricted eating. That means followers should fast for a specified number of hours – typically 16 to 20 per day – while freely consuming foods within a designated four- to eight-hour period.
To answer these questions, it helps to understand the basics of human metabolism.