How a thin person with diabetes reversed her type 2 diabetes

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Fasting to reverse type 2 diabetes

I received a letter from reader Sarah, who has successfully used low-carbohydrate high-fat diets and intermittent fasting to reverse her type 2 diabetes. Interestingly, she is not particularly overweight as measured by body mass index, yet still suffered from T2D. At her heaviest, she only had a BMI of 24.9, which puts her in the ‘normal’ range. She writes:

The letter

I immigrated to US from P.R. China in the end of 1998 when I was 31 years old; I weighed about 55 kg (121 lbs). While I was in China, I lived thousands of miles away from my family, so I had sort of an intermittent fasting life style from age 19 to 31 years old. The meals in China were mostly vegetables and very little protein. I had an annual physical check up every year, but was never told of any abnormal blood results.

After I immigrated to the U.S., my lifestyle suddenly changed from one meal per day to three meals consisting of mainly grains with little fat and protein. I gained about 25 pounds (11 kg) in a couple of years, my weight did not continue going up. My heaviest was about 145 pounds (66 kg). When I was diagnosed with diabetes in Dec 2004:

  • Weight: 142 pounds (64 kg)
  • Height: 5 feet 4 inches (163 cm)
  • HbA1c: 9.4
  • FG: 214

I was told to exercise, so I started yoga shortly after my diagnose. I lost about 10 pounds (5 kg) and 2 inches (5 cm) from my waist but still required metformin. In the spring of 2005, I relocated to Galveston from Houston because of my work as an engineer. My endocrinologist sent me to a nutritionist who measured my after meal glucose in her office, it was near 200 mg/dl (11.1 mmol/l) three hours after lunch which was only one low-fat pita bread. I was devastated, my previous family doctor always told me that if I exercise daily, my blood sugar will come down to normal, so I believed him. I was doing my yoga every day, but I thought that would be enough.


I volunteered to Joslin Diabetes Center’s clinical research in July 2006, and traveled to Boston as a research subject. I noticed I had gained about 5 pounds (2 kg) after adding 5 mg of glyburide so I stopped. In Boston, I was told that I need to gain muscle and reduce body fat because my weight was 144 lbs (65 kg) and my total body fat was 32.3% from DXA result.

After returning to Galveston from Boston, I started to add running and weights, and my weight went down to 132 lbs (60 kg) in a couple of months, and noticed my blood sugar would drop about 100 points (from 240 to 140 mg/dl – 13.3 to 7.8 mmol/l) in 10 minutes on treadmill. So I keep running about 45 minutes five times a week and doing weights about 20 minutes three time a week, and a couple of hours of yoga every week.

My weight would fluctuate from 132 lbs (60 kg) in winter and climb to 145 lbs (66 kg) in summer. My waist fluctuated from 30 to 31 inches (76 to 79 cm). I watched my carb intake according to the American Diabetes Association food plan, and noticed I could never consume the carb recommendations without elevating my blood sugar through the roof. As a matter of fact, my blood sugar will spike to about 100 points with ¼ of a slice of bread for lunch. I tested over and over, I could not explain. However, I corrected my after meal spikes with running on treadmill for 10 to 15 minutes every lunch.

In about 2nd quarter of 2009, I started a vegan diet which consisted mainly of grains, beans, vegetables only not even eggs or cheese, after watch PBS on one Saturday. Vegan diets supposed to reverse type 2 diabetes, as claimed by vegan promoters. During this period, I noticed my triglycerides had climbed up from 85 to 228, and my thyroid TSH also went up. After I got my lab test from Jan 21 2011, I decided to end my low-fat vegan experiment. I started my experiment with one problem, then I ended with more problems. I attended the vegan doctor’s presentation in Houston, and asked him about my triglycerides, he could not explain to me. The vegan diet did not help me with my diabetes, but I learned valuable information about how to use food as medicine. I also learned with increase in carbs, my triglycerides will go up which is a bad sign for my heart.


In February 2011, I started to experiment with the low-fat vegetable diet, after about a year, all my co-workers and my friends noticed my skin and palm turned into a green yellowish and my hands and feet were cold all the time with swelling. My face swelling every morning and my hands and feet swelling in the afternoon. I realized there is something wrong with my experimental food plan. I was told it is a degenerative disease so I accepted my fate. Continued with low-fat vegetables almost no saturated fat diet. Internally, I experienced fatigue every day which I could not explain.

By Oct 2014, my HbA1c climbed to 7.9, I almost broke down in my endocrinologist’s office. He comforted me and said it is not a big deal, he sees patients with HbA1c above 10 every day. I am one of his good patients.

I knew the grains triggered my blood sugar spike, so I started eliminate all grains and beans from my diet completely, but I was still afraid of fat especially saturated fat. I bought Dr. Richard Berstein’s books, he stated rib-eye steak is better than the lean steak for diabetes. I was shocked. Fat would give me diarrhea since I was a little girl, so I have been avoiding eating any saturated fat all my life. I grew up in food rationing era in China where almost no saturated fat was available from markets beside government stores.

So I started to understand the reasons for why vegan never worked for me. It was not dietary fat that caused me to be diabetic. I had eaten almost no fat in my whole life. I added saturated fat such as beef, butter and coconut oil to my diet, I found the Diet Doctor website. Dr. Andreas’s experiments in a diabetes conference meal was very similar to my own experiments. With the ketogenic diet, I was able to reduce my HbA1c from 7.9 (Oct 2014) to 5.9 (June 2015) in about eight months. I kept my carb intake to about 20 grams which mainly came from vegetables.

SarahXieApr2017By August 2015, I discovered Dr. Fung through I have been practicing intermittent fasting ever since. By March 2016, my HbA1c was 5.6. I lost about 12 lbs (5 kg) since I started the ketogenic diet (Nov 2014) my waist is 28.5 inch (72 cm), and weight 127 to 130 lbs (58 to 59 kg) through out a month period. I no longer have swelling on my face, hands, and ankles.

Since I started the ketogenic diet, my blood sugar would surge during exercise by about 80 points. For example, I would start at 110 mg/dl (6.1 mmol/L) before tennis, after 45 minutes my BG would 195 mg/dl (10.8 mmol/L) I tested over and over. I tried to use chocolate or cheese before exercising, none of which was able to lower or keep my blood sugar from surge. Out of desperation, I took a teaspoon of coconut oil then went on exercising, I found my blood sugar is remarkably stable during and after exercising. Before I found the secret of coconut oil, I could not begin to walk my dogs with blood sugar at 90 mg/dl (5 mmol/L), because it would surge to near 200 mg/dl (11.1 mmol/L), now I can take a teaspoon of coconut oil, then go to do exercising without experience any blood sugar surge. I am no longer depressed about being a diabetic.


That’s amazing work, Sarah. With these detailed records, you can see how LCHF and IF help even with a so-called ‘thin’ diabetic. Asians tend to get type 2 diabetes at a lower BMI than North Americans, with the average Chinese type 2 diabetic having only a BMI of 23.7 at diagnosis, not unlike Sarah. Even with a waist of 31 inches (79 cm), you can have type 2 diabetes. The important factor here is the intraorganic deposition of fat (inside the liver and pancreas) rather than the total fat mass.

Nevertheless, the pathophysiology of ‘regular’ and ‘thin’ diabetes is similar, and responds equally well to dietary interventions. It’s striking that even 10 years of diabetes on medications can be reversed completely since an HbA1c of 5.6 without medications defines Sarah as non diabetic. Congratulations!

Jason Fung


How to Reverse Type 2 Diabetes

Intermittent Fasting for Beginners

A Ketogenic Diet for Beginners

Top videos about type 2 diabetes

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Earlier with Dr. Jason Fung

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Dr. Fung has his own blog at He is also active on Twitter.

His book The Obesity Code is available on Amazon.

The Obesity Code

His new book, The Complete Guide to Fasting is also available on Amazon.



  1. Peter
    Congratulations Sarah

    I find the comments about the "sugar surge" even on a LCHF diet very interesting and wonder what is causing this and whether it can in part explain my own situation. I am a none diabetic but do have access to a blood sugar meter and my blood sugar is invariably 5.3. That is 5.3, exercising, 5.3, 2 hours after a meal, 5.3 first thing in a morning, 5.3 on a 24 hour fast. It never varies which means (I think) that my liver must be manufacturing the glucose from protein to maintain this level ?. Needless to say that I find it very difficult to get into Ketosis which is disappointing. I have done a 24hr fast on the back of 3 days of zero carbs and my blood sugar did fall to 5.1.

    I am 63 yrs of age, male, 25.1 BMI and do 16:8 fasting every day. I eat <50g carbs per day and <20g on most days.

  2. Lawrence

    Thank you for sharing your experiences, illustrating the efficacy of low carb dieting, especially used in conjunction with intermittent fasting. The record of your experiences contributes to a growing amount of evidence, amassed from a multitude of personal experiences, about how the standard dietary advice, or even the much touted vegan dietary propaganda, does not work for most people. What makes your case particularly compelling is that you did a lot of self-experimentation, and you were dedicated enough to record detailed measurements. Your story is one that I think I can share with anyone who has doubts about this way of eating. Keep up the good work. You are truly an inspiration.


  3. rudi klaiber
    would like to know if water or intermittent fasting would help for melasma?
  4. Lynn Ellis
    Congratulations Sarah! I was diagnosed with T2 in March of 2017. I am a 70 year-old female and at that time I weighed 155.6 lbs. I had had my stomach stapled 38 years ago and lost 69 lbs. (from 219.5), at that time, but still ate the wrong things and my weight bounced around, even though I can't eat much at one meal. The Diabetic Educator told me NOT to give up anything, but everything in moderation. Like you, my blood sugar spiked if I even looked at bread, flours, sugars. I found the Keto lifestyle and switched around May or June 2017. I did really well lowering my blood sugars, A1C to normal levels, lowering bad chol, raising good chol, and my weight is now around 100 lbs. Then this past May I had an unexplained blood loss and my hemoglobin went down from 135 to 85. Possibly a result of the stomach surgery. I had scopes but nothing showed, except some inflammation in my stomach (what they could see of it). I've been on iron ever since and it's back to normal. Since then my blood sugars have been all over the place and my last A1C results showed it increased from 5.6 to 7. The first thing my DE said was, 'You'll have to go on medication." No, said I. I have intense anger attacks coming out of nowhere and I have no idea why, except for my bouncing blood sugars. Needless to say, I'm depressed and very discouraged over this and have no idea what is causing it. I absolutely DO NOT want to lose anymore weight, but am having trouble figuring out how to put a few pounds back on, or even maintain it without making my sugar go crazy. I have Dr. Fung's book and I read it cover to cover. I want to try IF, however, don't want to lose weight. I would really appreciate receiving some tips from Dr. Fung or one of his team, or anyone else experiencing this. Thank you so much.
  5. Cynthia
    Thank you so much Sarah! I am a normal weight 59 year old female with blood work, BMI and waist circumference that all suggest good health but I had a DEXA scan in 2012 for bone density and found that although my bone density was good, I was a TOFI (thin on the outside and fat on the inside) with a total body fat percentage of 33.3%.

    I'm struggling with using KETO and IF because of recurrent fatigue, brain fog, nausea and dizziness within a couple of hours of eating. I've experienced this since childhood (always high sugar, high-processed food diet) and thought that it was hypoglycemia because even though I wasn't hungry, self-medicating with sugar would resolve it. I just read The Salt Fix and now believe it's probably just Keto Flu that is much more stubborn than the tips offered on Diet Doctor can alleviate.

    Like Lynn Ellis above, I would appreciate receiving some tips from Dr. Fung or one of his team, or anyone else with experience in resolving blood sugar/insulin/metabolic/hormone issues for those of us who should not lose weight. Thank you so much Diet Doctor!

  6. 1 comment removed
  7. CaraT
    Congratulations to Sarah on her achievements - really well done.

    I was diagnosed as 'prediabetic' 18 months ago. I was a slim, fit 68 year old, BMI 19.5, I took regular exercise and had a good diet, as well as having been on the 5:2 diet for 4 years.

    Consequently, I was shocked at the diagnosis (HbA1c 43mmol/mol) and immediately read a lot and reduced my carb intake to between 20 and 50g per day. I lost half a stone, reducing my BMI to 18.5. I have used a blood glucose monitor several times a day to inform me as to how my levels are going. Over the past 18 months. my HbA1c has been checked every few months with results of 43, 44, 43 and, yesterday, 45 mmol/mol. I don't know what I can do now. There is clearly an issue with my pancreas but I don't know what it is. None of the recommended protocols have worked for me. It seems as if I am trapped in a restricted, albeit healthy, diet but it is having no impact on blood glucose levels. I have read that I'm not alone in this situation - why isn't there more appropriate advice available to people like me?

  8. Henry Chin
    Congrats Sarah on your T2 reversal. Both my parents are from China and both had diabetes so my doctor said that my diabetes was hereditary and I was destined to be on medication like my parents. This diagnosis came during a check-up when I was 50 yrs old. I had the triad as the doctor called it at the time of my check-up meaning triglycerides, blood pressure and glucose levels were all high. He prescribed 3 medications to take care of each of the conditions. Over the course of 3 months on medication and changing my diet my triglycerides went normal and so did my blood pressure. Now a little about my body, I'm a male, 5'-9" tall, weight of 148 lbs., exercised quite a bit regularly. I went on the traditional diet for people with T2 but I am not a typical T2. So after changing my diet and being on prescribed medications for my symptoms my numbers all looked good. The doctor kept insisting I continue to take all the medications because it lowered all my numbers but I stopped the meds for triglycerides and the high blood pressure. The blood pressure med was doing crazy things to my body and that was the main reason for stopping. I no longer have any high triglycerides or blood pressure readings due to my diet. However, I lost a lot of weight with the new diet and trimmed down to 130lbs which is way to light for me. I changed my diet so i could put back some weight but it had consequences with my glucose levels.

    So 7 years later, I am 57 with high out of control glucose levels of 10.2 A1c and still on higher doses of meds and was prescribed Trulicity on top of my current meds to get my glucose numbers down (my glucose meter reads 200-245 every morning) . This was an eye opener as this meant injections once a week. I am still active exercise wise, low body fat, my body weight is 136 lbs and lifting heavy weights 4 times a week to maintain weight. So before I start the Trulicity I wanted to try one more time to really get my numbers down without increasing my meds. I experimented by fasting on a Saturday with nothing but water and no meds and saw my numbers drop to 163 at 16 hrs fasting to 144 at 20 hrs fasting. This somewhat gave me some semblance of hope that I could lower my A1c. So I had a big dinner that night (hot pot) and was eager to see my readings the Sunday morning. It came in at 148 so not that bad at all but I can't fast everyday for 22 hrs. I stopped all meds for a few days to see where my numbers are going and each day the readings went up. Monday it was 208, Tuesday it was 265. I went back on the meds but this time I cut out all grains whether it was whole wheat bread or brown rice. The readings for the next few days on the strict diet are W-231, Thurs-172, Fri-186, Sat-?, Sun-160, Mon-156,Tue-179. So experimenting with food right now and also trying to maintain my current weight with beef, chicken, pork, fish, vegetables, boiled eggs, protein drinks, apple-cider with water, and cinnamon tea. Hope this helps anyone trying to get their A1c down. This is a process and I'll keep experimenting and take better notes on types of food eaten, and exercise types whether weights or high cardio (I do notice numbers drop a bit when doing high cardio). My last thing I need to try is better sleep habits as I'm only sleeping less than 5 hrs a night sometimes less to get to my goal of 130. Would love to work/share some insights with others to get diabetes under control.

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