Changes in Insulin Sensitivity on a Low-Fat Plant-Based Diet

Article written and reviewed by Cyrus Khambatta, PhD
Published February 1, 2017

It’s always a rare opportunity to learn about the day-to-day life of people living with both type 1 and type 2 diabetes. While everybody has their own individualized methods for controlling blood glucose, preserving insulin sensitivity, performing frequent exercise and taking medication, the one puzzle piece that unites many living with diabetes is simple:

Unfortunately, many people living with diabetes suffer from a serious lack of education about the actual cause of blood glucose variability. And it’s not their fault.

There seems to be a gross miss understanding of diabetes nutrition, which has resulted in alarmingly high rates of diabetes across the U.S. and across the world. On one hand, our country has some of the best medical care in the world. On the other hand, understanding exactly what to put into your mouth when living with diabetes has become an endlessly confusing question with a multitude of misleading answers.

That’s exactly why we put on the Mastering Diabetes Retreat in Southern California in January 2016. It provided us with an opportunity to connect and learn from individuals living around the world with both type 1 diabetes and type 2 diabetes.

I co-hosted the retreat with many extremely talented individuals – Jewels Brown and Robby Barbaro. In addition, we had top-notch medical support from Kylie Buckner RN, MSN, and Dr. Nancy Bohannon M.D., a diabetes endocrinologist practicing in San Francisco. This all-star team of diabetes experts included Stefanie Dougherty, and our mission was to instruct, inspire and motivate people living with both type 1 and type 2 diabetes to understand a completely new version of nutrition and fitness for diabetes management, from the ground up. Watch this video for an idea of how much fun we had:

Retreat Protocol

Step 1: On day 1 we transitioned everyone to a low-fat, raw food vegan diet. We chose a raw diet in order to simplify food preparation, make exceptionally tasty food, and because a low-fat, raw-food vegan diet is quickly becoming the new gold-standard for reversing insulin resistance in a repeatable manner.

Step 2: We maintained all individuals on this diet for 4 days in a row.

Step 3: We encouraged all participants to exercise twice per day – once in the middle of the morning for 30-45 minutes and once in the middle of the afternoon for 30-45 minutes.

Step 4: We hosted 3 lectures per day about the following topics:

  • Blood glucose variability
  • Emotional eating
  • Intermittent fasting
  • Exercise
  • Insulin resistance
  • Safely reducing medication
  • The biology of insulin
  • Glycogen: the forgotten fuel
  • And much, much more...

Step 5: We attached continuous glucose monitors (CGMs) to 6 individuals in order to understand the acute changes in blood glucose that occur when transitioning to a low-fat plant-based diet


In this article, I will report on only on the acute changes observed in 3 individuals living with type 1 diabetes, to highlight the profound difference a low-fat plant-based diet is capable of producing in a short period of time.

Simply stated, the results were astounding.

Participant #1:

  • 13-year old female
  • Diagnosed with type 1 diabetes in 2013
  • Most recent A1c: 12.0%
  • Average fasting blood glucose: 200+ mg/dL

Participant #2:

  • 19-year old female
  • Diagnosed with type 1 diabetes in 2001
  • Most recent A1c: 6.3%
  • Average fasting blood glucose: 152 mg/dL

Participant #3:

  • 25-year old female
  • Diagnosed with type 1 diabetes in 1998
  • Most recent A1c: 6.9%
  • Average fasting blood glucose: 142 mg/dL


As you can see, participant #1 entered the retreat with an alarmingly high A1c value of 12.0%, and was using an average of 70+ units of insulin per day. Given her diet and lack of diabetes education, her blood glucose values remained above 200 mg/dL at all times. By reducing her fat intake, she was able to reduce her insulin usage by almost 50% in 4 days, while increasing her whole carbohydrate intake, for a combined insulin sensitivity increase of 245%.

Participants #2 and #3 both entered the retreat with great A1c values of 6.3% and 6.9%, respectively. Despite these A1c values, both participants experienced significant increases in their insulin sensitivity by dropping their fat intake below 20 grams per day.

Participant #2 more than doubled her carbohydrate intake while reducing her insulin usage by 33%. Participant #3 increased her carbohydrate intake by 62% while still recognizing a 17% drop in insulin usage.

The common threads that unite these 3 individuals are simple:

  • They each reduced their total dietary fat intake to less than 20 grams per day
  • They each increased their whole carbohydrate intake significantly
  • They each reduced their insulin usage in order to minimize hypoglycemia

How to Calculate Insulin Sensitivity

In each of these scenarios, insulin sensitivity was calculated as the ratio of 24-hour carbohydrate intake to insulin usage within the same 24-hour period. This gives a metric for the amount of insulin required to effectively metabolize carbohydrates, and is a metric that combines both short-term and long-term insulin.

In each of these scenarios, insulin sensitivity was calculated as the ratio of 24-hour carbohydrate intake to insulin usage within the same 24-hour period. This gives a metric for the amount of insulin required to effectively metabolize carbohydrates, and is a metric that combines both short-term and long-term insulin.

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About the author 

Cyrus Khambatta, PhD

Cyrus Khambatta, PhD is a New York Times bestselling co-author of Mastering Diabetes: The Revolutionary Method to Reverse Insulin Resistance Permanently in Type 1, Type 1.5, Type 2, Prediabetes, and Gestational Diabetes.

He is the co-founder of Mastering Diabetes and Amla Green, and is an internationally recognized nutrition and fitness coach who has been living with type 1 diabetes since 2002. He co-created the Mastering Diabetes Method to reverse insulin resistance in all forms of diabetes, and has helped more than 10,000 people improve their metabolic health using low-fat, plant-based, whole-food nutrition, intermittent fasting, and exercise.

Cyrus earned a Bachelor of Science in Mechanical Engineering from Stanford University in 2003, then earned a PhD in Nutritional Biochemistry from the University of California at Berkeley in 2012. He is the co-author of many peer-reviewed scientific publications.

He is the co-host of the annual Mastering Diabetes Online Summit, a featured speaker at the Plant-Based Nutrition and Healthcare Conference (PBNHC), the American College of Lifestyle Medicine Conference (ACLM), Plant Stock, the Torrance Memorial Medical Center, and has been featured on The Doctors, NPR, KQED, Forks Over Knives, Healthline, Fast Company, Diet Fiction, and the wildly popular podcasts the Rich Roll Podcast, Plant Proof, MindBodyGreen, and Nutrition Rounds.

Scientific Publications:

Sarver, Jordan, Cyrus Khambatta, Robby Barbaro, Bhakti Chavan, and David Drozek. “Retrospective Evaluation of an Online Diabetes Health Coaching Program: A Pilot Study.” American Journal of Lifestyle Medicine, October 15, 2019, 1559827619879106. https://doi.org/10.1177/1559827619879106

Shrivastav, Maneesh, William Gibson, Rajendra Shrivastav, Katie Elzea, Cyrus Khambatta, Rohan Sonawane, Joseph A. Sierra, and Robert Vigersky. “Type 2 Diabetes Management in Primary Care: The Role of Retrospective, Professional Continuous Glucose Monitoring.” Diabetes Spectrum: A Publication of the American Diabetes Association 31, no. 3 (August 2018): 279–87. https://doi.org/10.2337/ds17-0024

Thompson, Airlia C. S., Matthew D. Bruss, John C. Price, Cyrus F. Khambatta, William E. Holmes, Marc Colangelo, Marcy Dalidd, et al. “Reduced in Vivo Hepatic Proteome Replacement Rates but Not Cell Proliferation Rates Predict Maximum Lifespan Extension in Mice.” Aging Cell 15, no. 1 (February 2016): 118–27. https://doi.org/10.1111/acel.12414

Roohk, Donald J., Smita Mascharak, Cyrus Khambatta, Ho Leung, Marc Hellerstein, and Charles Harris. “Dexamethasone-Mediated Changes in Adipose Triacylglycerol Metabolism Are Exaggerated, Not Diminished, in the Absence of a Functional GR Dimerization Domain.” Endocrinology 154, no. 4 (April 2013): 1528–39. https://doi.org/10.1210/en.2011-1047

Price, John C., Cyrus F. Khambatta, Kelvin W. Li, Matthew D. Bruss, Mahalakshmi Shankaran, Marcy Dalidd, Nicholas A. Floreani, et al. “The Effect of Long Term Calorie Restriction on in Vivo Hepatic Proteostatis: A Novel Combination of Dynamic and Quantitative Proteomics.” Molecular & Cellular Proteomics: MCP 11, no. 12 (December 2012): 1801–14.

Bruss, Matthew D., Airlia C. S. Thompson, Ishita Aggarwal, Cyrus F. Khambatta, and Marc K. Hellerstein. “The Effects of Physiological Adaptations to Calorie Restriction on Global Cell Proliferation Rates.” American Journal of Physiology. Endocrinology and Metabolism 300, no. 4 (April 2011): E735-745. https://doi.org/10.1152/ajpendo.00661.2010

Bruss, Matthew D., Cyrus F. Khambatta, Maxwell A. Ruby, Ishita Aggarwal, and Marc K. Hellerstein. “Calorie Restriction Increases Fatty Acid Synthesis and Whole Body Fat Oxidation Rates.” American Journal of Physiology. Endocrinology and Metabolism 298, no. 1 (January 2010): E108-116.