New Year's resolutions: What you need to know about intermittent fasting

  • Emmaline Rasmussen

    Emmaline Rasmussen

Submitted by NorthShore University HealthSystem

As we start off the New Year, many of us are looking to get in shape and lose weight. Is intermittent fasting the way to shed those extra holiday pounds?

Emmaline Rasmussen, clinical research dietitian at NorthShore University HealthSystem, weighs in on the latest "fad" of intermittent fasting and why it might not be healthy for everyone.

What is intermittent fasting?

This new diet and weight loss trend involves variations of fasting, allowing people to consume the foods they like during specific times or on certain days, and restricting themselves the remainder of the time.

There are a few variations of intermittent fasting, with one of the most common methods being the 16/8 method. This is where eating is restricted to eight-hour periods, usually between 11 a.m. and 7 p.m., then you fast for 16 hours.

What happens to the body during a fast?

When your body fasts and your insulin drops, a fat-burning hormone called glucagon is released, causing the body to utilize alternate energy sources (such as fat stores) in the absence of glucose.

This can help promote weight loss, and some proponents of the diet claim it can help reduce insulin resistance, reduce LDL (bad) cholesterol and triglycerides and improve inflammatory markers.

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People have also reported enhanced productivity, mental clarity, brain function, and memory while in a fasted state.

Why is intermittent fasting trendy now?

Intermittent fasting allows one to eat "normally" during non-fasting periods, which makes it easier to adhere to the restrictions during fasting.

Since the fasting periods are relatively short-lived, compliance may be easier, which allows one to achieve better results.

In other words, one can enjoy the things they like during non-fasting periods (within reason) which makes them feel less restricted while still achieving their goals.

Though intermittent fasting can lead to some modest weight loss, the amount of weight lost is not significantly different compared to other diets such as calorie restriction alone. Many people who follow an intermittent fasting schedule choose it for the other potential benefits.

Who should not do intermittent fasting?

This is not appropriate or safe for everyone. Talk to a dietitian and doctor first to ensure you are following a healthy diet and fasting regimen.

Do not try it if you take certain medications such as medications that must be taken with food.


You should not try this diet if you are insulin dependent or have a tendency to become hypoglycemic, are battling or have a history of an eating disorder, or have certain psychiatric conditions (such as schizophrenia and bipolar disorder).

The bottom line

If you decide to try the intermittent fasting trend, discuss it with your health care provider, proceed with caution and try to eat a reasonable, healthy diet (allowing for some indulgences) during non-fasting hours.

And keep in mind you can start small -- many people start with a 12-hour fast and work their way up to the 16-hour fast/eight-hour feed schedule over the course of a week. Evaluate how you feel one to two weeks in and adjust accordingly.

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