RD Weighs in on Intermittent Fasting

Curious about intermittent fasting for weight loss? We asked our Wellness Dietitian, Renee Greene, RD, LDN, to weigh in on this popular diet and health trend.

What is Intermittent Fasting?

Intermittent fasting (IF) is an eating pattern that cycles between periods of eating and fasting. During periods of fasting, you are instructed to eat either a very small amount or nothing at all depending on which IF method you choose.

Types of Intermittent Fasting

The idea of intermittent fasting was originated by a book called “The Fast Diet” by Michael Mosley, MD, and Mimi Spencer. There are several different methods of intermittent fasting to choose from, but all follow the same rule -- split either the day or week into periods of eating and fasting. The most common methods are:

  1. The 16/8 method: Restrict your daily eating window to an 8-hour period and then fasting for the other 16.
    The theory is that this will decrease the amount of calories consumed each day compared to eating from the time you wake up until the time you go to bed. By not putting a restriction on the types of food you eat, the goal is for you to be able to incorporate this into your lifestyle and do it for the long haul. However, you will not decrease your overall calories if you choose high-calorie foods. This may be beneficial for those that mindlessly eat throughout of the day and can be combined with another diet to include healthy choices.
  2. The 5:2 method: Eat normally or “ad libitum (as you wish)” 5 days out of the week and fast for two days – eating only 500-600 calories per day.
    Foods recommended are lean proteins, vegetables, fruit, water, and calorie-free drinks. On normal non-fasting days, participants are told they can eat whatever they want. Exercise is encouraged on the five non-fasting days while not as much on the two days you are fasting. (This is probably due to the lack of energy you have from only eating 500-600 calories on those days). Once the weight loss goal is reached, fasting occurs one day each week for maintenance.

Positive: In theory, this way of dieting alters the way your body attains energy and should reduce the amount of calories you consume overall to cause weight loss without altering metabolism. And studies have found that weight loss in general may help prevent chronic diseases such as heart disease and diabetes.

Negative: This diet is not recommended for those individuals with diabetes, children, the underweight, or with eating disorders, pregnant, or with chronic illnesses or disease states. During periods of fasting, there may be symptoms of light-headedness, dizziness, tiredness, nausea, fatigue, and/or headache.

Bottom Line: Any diet that restricts calories enough will cause weight loss. But, this way of eating may be tough for some to follow long term and may cause temptations to binge during the “non-fasting” periods.

If you’ve heard the buzz about intermittent fasting and wondered if it would work for you, a conversation with your primary care provider is a smart place to start. Don’t have an established primary care provider? Catawba Valley Medical Group has you covered with 17 family medicine practices located in Catawba County and surrounding regions, some of which are now taking same-day/next-day appointments. Click here to find a provider close you.

Categories