Will Intermittent Fasting Help Your Type 2 Diabetes?

by Mary Shomon Patient Advocate

Intermittent fasting has become a popular way of eating for weight loss and other health conditions. Research has found that following an intermittent fasting program may help improve — or even reverse — prediabetes and type 2 diabetes in some cases. Let’s take a look at intermittent fasting and some of the recent research.

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What Is Intermittent Fasting?

Intermittent fasting–also known as “therapeutic fasting”–refers to a program involving scheduled periods with no food intake. During fasting, unlimited quantities of very-low-calorie drinks–such as water, coffee, tea, broth, and bone broth–are permitted. A multivitamin supplement is also recommended for people practicing intermittent fasting.

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How Does Intermittent Fasting Work?

Carbohydrates–especially simple carbs like sugars and low-fiber grains–quickly break down into sugar. If your cells don't use all this sugar as energy, it gets stored as fat. Insulin is needed to get glucose/sugar into fat cells.

Between meals and during fasting periods, insulin levels drop, and fat cells release free fatty acid and glycerol, which then the fat is burned off, causing weight loss.

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What Are the Benefits of Intermittent Fasting?

In addition to weight loss, intermittent fasting has other benefits:

  • A 2013 study published in the British Journal of Nutrition found that intermittent fasting improved insulin sensitivity and controlled weight better than calorie restriction.
  • A recent study of obese men with prediabetes found that “early time-restricted feeding”–eating only during an early eight or ten-hour period of the day starting at 7 a.m.–significantly lowered insulin and improved insulin sensitivity.
Key intermittent fasting methods.
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What Are the Different Intermittent Fasting Plans?

There are three main intermittent fasting methods to consider.

  • With the 5:2 plan, you eat normally five days a week, and do a partial fast of 500 to 600 calories from protein and fat the other two days. The 5:2 plan has the most research data supporting its effectiveness.
  • With 24-hour fasting, you eat no food for 24 hours, one to three days a week.
  • With a time-restricted plan, you eat all the day’s calories within an 8 to 12-hour block each day and fast the remaining 12 to 16 hours.

The 5:2 Plan

A 5:2 plan includes two days a week of eating only fat or protein, not to exceed 500 calories. Permitted foods include, for example, eggs, fish, meat, poultry, or nuts. You can also have unlimited low- or no-calorie beverages. The other five days you eat healthy foods, without counting restricting calories or avoiding carbohydrates. For even better results, control carbohydrates on unrestricted days.

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The 24-hour Fasting Plan

To follow the 24-hour fasting plan, you eat no food for 24 hours, one to three days a week. You can, for example, eat dinner, then fast for 24 hours, and then eat dinner again the next evening. During the fasting period, you can drink unlimited amounts of low- or no-calorie beverages. When eating, focus on healthy, lower-carbohydrate foods.

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Time-restricted Plans

With a 16-8 or 12-12 time-restricted plan, you eat all the day’s calories within an 8 to 12-hour block each day and fast the remaining 12 to 16 hours. During the fasting period, you can drink unlimited amounts of low- or no-calorie beverages. When eating, focus on healthy, lower-carbohydrate foods.

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Healthy Eating During Intermittent Fasting

For the best results with intermittent fasting, here are some healthy eating tips:

  • Avoid – or significantly limit your intake of – simple carbohydrates, sugars, and refined grains, like cereal, rice, and baked goods.
  • Focus on eating vegetables, low-sugar fruits, lean protein sources, and healthy fat.
  • Don’t snack between meals.
  • Don’t snack or eat at night.
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Intermittent Fasting for Prediabetes and Type 2 Diabetes

If you have prediabetes or type 2 diabetes, there is evidence that intermittent fasting may be helpful to your treatment.

A 2018 study published in the British Medical Journal found that intermittent fasting had significant benefits for people with prediabetes or type 2 diabetes. The patients followed three 24-hour fasts per week for several months.

The patients were given a book, The Complete Guide to Fasting, by Jason Fung and Jimmy Moore, as their guide.

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What Were the Results?

Specifically, by following the study protocol:

  • 100 percent of the patients studied were able to stop their insulin therapy within three weeks while managing blood sugar levels
  • Two-thirds of the patients also discontinued all their type 2 diabetes medications.
  • 100 percent of the patients reduced their hemoglobin A1C (HbA1C) levels
  • The study group also reduced or reversed insulin resistance and lost significant amounts of weight.
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Should You Consider Intermittent Fasting?

If you have type 2 diabetes–and especially if you have challenges managing your blood sugar, you require insulin therapy, or are taking numerous type 2 diabetes medications–it is advised to consult with a health care provider before entering any intermittent fasting program that is not supervised by medical experts. If you follow an intermittent fasting program, it’s also important that your blood sugar levels are carefully monitored, as you may be able to lower or even stop your insulin therapy or type 2 diabetes medications.

Mary Shomon
Meet Our Writer
Mary Shomon

Mary Shomon is a patient advocate and New York Times bestselling author who empowers readers with information on thyroid and autoimmune disease, diabetes, weight loss and hormonal health from an integrative perspective. Mary has been a leading force advocating for more effective, patient-centered hormonal healthcare. Mary also co-stars in PBS’ Healthy Hormones TV series. Mary also serves on HealthCentral’s Health Advocates Advisory Board.