Can Intermittent Fasting Help Us Lose Weight?

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Recently, there has been a lot of buzz around Intermittent Fasting and its effect on weight loss.  But does this really help us lose weight? 

What is Intermittent Fasting?

Before we dig into this topic, let’s first define what is meant by Intermittent Fasting.  Intermittent Fasting, also called Time Restricted Eating, refers to an eating pattern that involves fasting, or not eating, for a period of time each day or week. According to the Mayo Clinic, some popular types of Intermittent Fasting include:

  • Alternate-day fasting. Eat a normal diet one day and either fast entirely or have one small meal (less than 500 calories) the next day.
  • 5:2 fasting. Eat a normal diet five days a week and fast two days a week.
  • Daily time-restricted fasting. Eat normally but only within an eight-hour window each day. For example, skip breakfast but eat lunch around noon and dinner by 8 p.m.

If we look at how metabolism works in the body, it would make sense that Intermittent Fasting could be beneficial.  When we eat food, it is broken down into sugar in the blood that our cells use for energy.  Insulin is the hormone that enables the sugar to leave our bloodstream and enter our cells to be used by the body for energy.  If our cells don’t use all of the sugar from the food that we eat, then this gets stored in our bodies as fat. The more fat cells our bodies have, the less efficiently our insulin can work to lower our blood sugar, leading to insulin resistance.  Higher blood sugar can also cause inflammation.  Insulin resistance and inflammation are highly linked to increased risk for chronic diseases such as diabetes, high cholesterol, hypertension, and obesity. 

It is thought that the mechanism for Intermittent Fasting producing weight loss is that during the period of fasting, insulin is lowered causing the fat cells to release their stored sugar to be used as energy by the body, which can result in weight loss.   

What does the research say?

One research study looked at two groups that both reduced their daily calories by 25%.  One group incorporated Intermittent Fasting and ate all of their calories in an 8-hour window, while the other group ate the same amount of calories without a time restriction.  At the end of the 12-month study, both groups lost similar amounts of weight and there were no differences between the groups related to weight loss.  Both groups also had similar improvements in blood pressure, lipids, blood glucose levels and other risk factors. 

What does this mean for us?

For most of us (excluding those who have diabetes, eating disorders, are pregnant or breastfeeding, or require food with medications), Intermittent Fasting does appear to be a safe strategy for modest weight loss.  When used as intended, it limits the time window for eating and therefore can reduce the number of calories that we eat during the day. 

There is a major pro and major con of Intermittent Fasting.


By limiting the amount of time that we are eating, it sets a natural stopping point for eating each night, which can greatly reduce nighttime boredom snacking, which is a challenge for many of us.


If we use our eating window as a license to eat as much as possible during that window, it can produce the opposite results.  It is still important to practice mindful eating and refer to our own calorie needs even while Intermittent Fasting.

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