May 17, 2021

Metabolic disease

#162 – Sarah Hallberg, D.O., M.S.: Challenging the status quo of treating metabolic disease, and a personal journey through a grim cancer diagnosis

"For a disease that everyone thought was chronic and progressive, to see people recover from it is quite astounding.” —Sarah Hallberg

Read Time 30 minutes

Note to listener: It’s with great sadness that we report that Sarah recently lost her battle with lung cancer. As such we’ve decided to republish her episode on April 3, 2022 to honor her, her amazing work, and her courageous cancer journey.

Sarah Hallberg was the Medical Director at Virta Health and a physician who spent nearly two decades treating patients with obesity and type 2 diabetes.

In the first half of this episode, Sarah discusses how she became a huge believer in the efficacy of carbohydrate restriction for the treatment of type 2 diabetes through her research and clinical experience. Sarah challenges the common beliefs about the role of dietary fat and carbohydrate on the plasma makeup of fatty acids and triglycerides. She also expresses the importance of understanding early predictors of metabolic illness—highlighting one particular fatty acid as the most important early predictor—before finishing with a discussion about how doctors might be able to personalize patients’ metabolic management in the future.

In the second half of this episode, Sarah tells the personal story of her own lung cancer diagnosis (skip to the second part of her episode on youtube here). She talks about dealing with her grief, deciding to continue her work while prioritizing her family, and how she devised a plan to extend her survival as long as possible.


We discuss:

  • How Sarah discovered the profound impact of carbohydrate restriction for reversing obesity and type 2 diabetes [3:15];
  • Prediabetes and metabolic syndrome: prevalence, early signs, and the importance of treating early [16:00];
  • Overview of fatty acids, how they are metabolized, and understanding what you see in a standard blood panel [29:15];
  • The relationship between diet composition and metabolic markers [35:15];
  • Why palmitoleic acid is such an important biomarker [48:15];
  • The best early indicators of metabolic disease [1:00:00];
  • Personalized management of metabolic illness [1:07:00];
  • Sarah’s cancer diagnosis and the beginning of her journey [1:15:15];
  • The emotional impact of a devastating diagnosis [1:27:15];
  • Sarah’s plan to extend survival [1:36:45];
  • Sarah’s aggressive treatment plan [1:47:30];
  • Life-threatening complications and the return of her cancer [1:59:00];
  • Sarah’s reflections on her approach to life with chronic cancer and balancing her time [2:11:00]; and
  • More.


How Sarah discovered the profound impact of carbohydrate restriction for reversing obesity and type 2 diabetes [3:15]

High-fat, low-carbohydrate diet for metabolic health 

  • Some people fear that a low carb, high fat diet will lead to increased insulin resistance and eventually cardiovascular disease
    • But a therapeutic, carbohydrate-restricted diet can reduce cardiovascular (CV) risk factors including triglycerides (TGs), improve glycemic control, and even reverse type 2 diabetes (T2DM) in most cases
    • Consuming fatty acids (FAs) in the context of a carb-restricted diet shows that the old saying “you are what you eat” is not accurate
  • FAs can be confusing to understand, but play an important role in both cardiovascular and diabetes risk

What led Sarah to focus on the management of diabetes?

  • Peter and Sarah met through a company called Virta Health, in which Peter is an investor and former advisor 
  • Sarah has been treating obese patients for more than 25 years, never would have thought her career would take this direction
    • Like others trained in the 1980s, Sarah learned in undergrad/master’s in exercise physiology and in med school the best way to address obesity was to eat a low calorie, low fat diet
    • But Sarah watched her patients become worse trying to follow this advice
    • She felt discouraged about primary care because she “felt like a legal drug dealer”
  • Sarah says a lot of the pivots in her career were motivated by anger, “and I was really angry at what was happening on the primary care level”
  • Indiana University Health asked her to start an obesity program
    • She was able to take time off to study the literature, which docs rarely have time to do
    • Listened to lectures by Dr. Steve Phinney and Jeff Volek

“I came to the conclusion … that what I had been saying for well over a decade to so many people was really not founded on good science and that the field of carbohydrate restriction, while still relatively in its infancy at the time, showed much more promise.” —Sarah Hallberg

Sarah’s obesity clinic

  • She ended up opening the obesity clinic as a carbohydrate restricted clinic
    • Patients lost weight but more importantly found that their diabetes was reversing, with normal blood sugar levels
    • We were pulling them off of insulin at rates that I could never have believed had I not been the physician who was taking care of these patients. It was astronomical, hundreds of units of insulin.”  
    • Most clinic patients had some kind of metabolic disease and T2DM was the most common 
  • To get institutional support for the clinic, she gave presentations to all the departments in the med center explaining the scientific evidence behind carb restriction
    • Surprisingly, she got no pushback
    • even got fellow members of the ambulatory quality committee to unanimously pass an amendment saying that all patients with metabolic disease should at least be provided the option of trying a low carb diet

“As we were seeing these huge changes of … patients just resolving their diabetes, I became really angry because I was like, ‘Where is this? Where’s this in the guidelines? How come I’ve never heard of this before?’ I mean, I hate to be overdramatic, but it truly is quite miraculous for a disease that everyone thought was chronic and progressive, to see people recover from it is quite astounding.” —Sarah Hallberg

Early studies by Sarah

  • Conducted an early unfunded study of metabolic improvements with carb restriction
    • Also looked at economic advantages because not requiring medication saves money for both the individual and the healthcare system as a whole (expanded on in a later paper)
  • Sarah has discussed the results of her research at the National Lipid Association and in a popular TED Talk that has been viewed more than 7 million times
  • She met Steve Phinney at a meeting of the Obesity Medicine Association, which “really changed the course of my life”
    • Peter has been trying to get Steve on the podcast 
    • Peter reached out to Steve when he began implementing some of the low carb principles
    • Peter had a pre-print copy of Steve and Jeff’s 2011 book The Art and Science of Low Carbohydrate Living (“which might have more highlights and post-its in it than any book I own”)
  • Like Sarah, he kept thinking it couldn’t be true because it seems counterintuitive


Prediabetes and metabolic syndrome: Prevalence, early signs, and the importance of treating early [16:00]

  • At meetings of the American Diabetes Association, Sarah found that doctors who treated patients for obesity understood her approach, but other specialists worried that it would cure diabetes but give the patient heart disease
    • Many doctors, including leaders, acknowledged it works but said patients could not stick with it, which was not what Sarah saw in her practice
    • Pioneering work of Steve and Jeff and Eric Westman was valuable, but Sarah thought they needed large trials focused on patients with T2DM
    • She says T2DM patients should be the target because biggest impact on that population
  • Sarah’s chance meeting with Steve at the Obesity Medicine Association led to funding for a large clinical trial that is just finishing now
    • Many papers have already come out of the trial, the latest of which (on prediabetes) was published on the day of this this interview
    • Latest paper studied patients with prediabetes [defined as having a hemoglobin A1c (HbA1c) level of 5.7 to 6.4] who received remote continuous support to maintain a ketogenic diet for 2 years
    • Reach the prediabetes range when fasting glucose is over 110 
    • But Sarah emphasizes that insulin resistance can cause significant problems in people who still have normal blood sugars
  • In this study, subjects had insulin resistance long enough that their pancreas and the β-cells could not make enough insulin to keep blood sugar normal, so and their blood sugar started to rise
    • Not yet to the T2DM level, but see the impact of insulin resistance as the pancreas has been overworked for far too long
  • Around 10% of the U.S. population now has T2DM 
    • much more concerning levels in different minority populations, which is a huge goal with improving health equity in this country
    • Level is “well into the teens” in Hispanic, African American, and Pacific Islander populations in US
  • In Peter’s podcast with Gerry Shulman about insulin resistance, they discussed the long-term course of diabetes 
    • Can have normal fasting glucose and fasting insulin but elevated postprandial insulin, which is an early sign of insulin resistance than can lead to high postprandial glucose
    • By the time someone is labeled “prediabetic” the process has been going on for 5 to 10 years
  • More than 1/3 of Americans are either prediabetic or diabetic 

“This should shock everyone to the core. … 88% of Americans are not in optimal metabolic health.”


{end of show notes preview}

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Sarah Hallberg, D.O., M.S.

Dr. Sarah Hallberg is a physician and exercise physiologist. The founder and Medical Director of the Medically Supervised Weight Loss program at Indiana University Arnett, she is also the Medical Director at Virta Health and an adjunct clinical assistant professor of medicine at Indiana University School of Medicine. An expert on metabolic control and type 2 diabetes, Dr. Hallberg is also the executive director of The Nutrition Coalition, a nonprofit organization that aims to strengthen national nutrition policy. Her TEDx talk “Reversing Type 2 diabetes starts with ignoring the guidelines” has been viewed more than 7 million times. Dr. Hallberg is board certified in internal medicine, obesity medicine, and lipidology. She received her bachelor’s and master’s degrees in kinesiology and exercise science from Illinois State University and her degree in medicine from Des Moines University.

Twitter: @DrSarahHallberg

Instagram: @sarahhallberg

Facebook: Sarah Hallberg

Disclaimer: This blog is for general informational purposes only and does not constitute the practice of medicine, nursing or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this blog or materials linked from this blog is at the user's own risk. The content of this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard, or delay in obtaining, medical advice for any medical condition they may have, and should seek the assistance of their health care professionals for any such conditions.


  1. as always, a great and informative podcast. unless I missed it, i would be interested in hearing Sarah’s opinion of the increased LDL-C/ apoB phenomenon that often occurs in patients on a ketogenic diet. At one point i think she was ven looking into following a surrogate marker of atherogenic process ( cIMT) in these patients. Most Clinical Lipidologists feel that the apoB elevation is dangerous- how does she deal with this clinically in her patients ?

    • Does it occur often? Following a keto-ish diet (at age 31) my LDL-C is 118 but apoB is 87.

  2. Love you both Peter and Sarah and so thankful for your work. I´d like to point out that metabolic dysfunction affects the autonomic nervous system so regaining metabolic health could affect your ability to have an erection and is not only necessarily related to microvasculature damage/healing. Best regards

  3. All I can say is WOW! As a mom, this was a tough one to listen too. It’s so easy to take my health and good fortune for granted. A HUGE thank you to Sarah for her primary work in Obesity, very eye opening, and for sharing a very personal story.

  4. Wow! What a conversation. Thank you, Sarah, for sharing your story. I am hearing more frequently about women in their 40s and 50s being diagnosed with lung cancer, also colon cancer. I wish you every day of strength and continued courage through this experience. Thank you, once again, for trusting us.

  5. Dear Peter and Sarah
    What a powerful podcast. As someone who struggles with pre-diabetes and a family who has the same circumstances this was extremely meaningful, but I never expected to have such a depth of awareness concerning health inequities and the powerful story Sarah shared about her journey with lung cancer. If she was someone in a marginalized community she would not be alive. I am so grateful for the meaningful sharing and the reminder that despite everything we are all terminal and that using what we know to advocate for wellness each day is the secret power. Thank you for this podcast. – Mary Catherine

  6. Thank you so much, Dr.Hallberg for sharing your amazing story! You are certainly using every precious minute to relish this life and educate, help and inspire along the way. Thank you, Dr. Attia for bringing us Sarah’s story and all the educational content. Heartfelt Thank you to both of you for your passion and dedication.

  7. Forgive me of my ignorance, but I’m not really seeing the value of the SCD1 enzyme as a biomarker when it seemingly tracks with serum triglyceride, which is established and easy to measure. A quick hypothesis as to why trigs stay “normal” in African Americans with frank diabetes could be explained by the inability to convert glucose to fat. Whether the bottleneck is in the desaturase enzyme or some other enzyme in the pathway is anyone’s guess and worth investigating.

    Could have done without all the guilt for having the means and wherewithal to navigate fighting cancer. Some aspects of “privilege” are innate to humanity itself and I’m deeply skeptical of calls for “equity” without defining just exactly what that means and the implications of implementing it. Admire Dr. Hallberg’s tenacity though in the face of a crushing diagnosis. Powerful testament in my mind to having a child/children. Very much reminiscent of Dr. Paul Kalanathi’s story.

    It strikes me that simply doing away with the agricultural subsidies that allow the processed “food” environment to thrive would do more to address health disparities than just about any one thing. The combined hedonic pleasure derived from eating SAD along with the financial incentive (“cheaper” direct price to the consumer than whole food alternatives) are a double whammy. Addressing the root causes of poverty in a productive manner would certainly be helpful as well. We spend more per capita educating our kids than pretty much all of the developed world and I don’t think we get a good return on investment. Maybe it’s time to experiment with vouchers.

    • I agree on the equity aspect of your comment. I think there are two ways one can address differences.
      1. Bring everyone down so everyone is treated the same and thus there is little difference in “equity”. Then the “problem” is solved! I am not for this and I suspect you and Dr. Hallberg are not.
      2. Look for ways to scale up processes so more people can have better – in this case – health care. It will not eliminate the “equity” problem but it will improve the human condition. Certainly, I would say that Virta is trying to do that with Type 2 diabetics and as a corollary I think this is Dr. Hallberg’s intent.

      Yes, the medical field has a major challenge in that the medical knowledge is asymmetric. Dr.s are not trying to hide information , but the whole field is tremendously complex. I am fairly intelligent and I have biochemistry and biological knowledge above the high school level, but gosh I am lost in the 1st hour of this talk about fatty acids. (software engineer not a Dr). Also Dr. Hallberg herself mentions that she decided to try a different approach to diet and health than was the “standard of care”. That battle is still going on even within the medical community.

      Anyway I hope we can get medical care going forward. That should be the goal.

  8. I do not cry, never have really been, not even when my parents passed. I have to say I cried like a baby listening to Sarah’s story. God bless you both for the advocacy for the people out here just trying to live. I really hope that Sarah beats the odds, and if you don’t beat the odds, know that your 12 yo was exactly correct! You have done a tremendous amount of good for the world in your time here, and we are all better off because of what you have done!

  9. To Sarah Hallberg

    I am a Type 1 diabetic physician (now retired) looking at 70 years of age. I consistently maintain HbA1c in the low 5s. For 15 of my 35 diabetic years I have followed a low carb lifestyle in my DM management and fully understand the benefit of this approach. I cannot express the amount of frustration that I have experienced at trying to spread this gospel, with the vast majority of colleagues, friends and acquaintances turning their heads in disbelief and denial. So many of us that follow these techniques, best exemplified by Richard Bernstein MD, are like a cult who preach to each other but are not listened to by the “authorities”. In my practice I routinely saw the ravages of DM, The existing dogma has maimed and killed many diabetics in my opinion – and they have been unaccountable. It has been a lonely journey, relative to the mainstream of medicine.

    I know that low carb works for diabetes. After all it is a metabolic disorder of carbohydrate metabolism, so cutting carbs is the treatment. There is increasing science defending this approach, but a lack of RCTs etc. Of course there is little funding for studies that do not involve financial profit potential. Just look at the number of low carb studies at the yearly ADA meeting, which is abysmal, and yet the treatment works. I wholeheartedly commend you in your energy and efforts to change this dogma that has existed, and certainly know the frustrations and obstacles that you must face.

    Those Type 1s of us that choose the low carb low insulin dose lifestyle live on the edge of hypoglycemia. Although. hypos are easily and safely treated with those taking small doses of insulin, the fear to so many practitioners in advocating this treatment is certainly influenced by med mal and liability. I would hope for better forms and more affordable glucagon like products in the future.

    I am a prior cancer patient as well now 9 yrs post treatment, and have some insight in to your challenges. I commend you so much for challenging the oncology given, in your treatment and searching for something that was better for you. It is so important to feel that you are on the best approach for yourself.

    You are a profound inspiration in all that you do. We greatly appreciate what you do and what you have done. You are a warrior in this long slow war of change in the treatment of diabetics.

    Peter Attia, you are also the best. Thank you especially for this podcast. I have followed you for over a decade now and your podcasts and writings have been an integral part of my medical beliefs. Please keep it up and keep teaching us. And above all, maintain your healthy skepticism of dogma, as true science does not exist without questioning and challenge.

    J. Daniel Jones MD

  10. I just watched this episode on YouTube. I will review Sara’s work on fatty acids amd diabetes.
    But, can I please say how perfectly human you’ve been to do this interview.
    You’ve brought profound intimate, decent, touching, wise humanity to The Drive today. I feel this exchange, this video and audio is just as helpful to our lives as are treatment videos.
    Encouraged and hopeful.
    A powerful revelation of delicate transparency.
    Thank you, Peter Attia, and, Champion Sarah Hallberg

  11. What an inspirational conversation. Sarah, you are doing God’s work, and your courage and dedication is inspiring. You are making a true difference in this world, and I know your children and family are so proud of you. My best wishes to you as you fight this disease.

    • Nice podcast. Sara May want to consider other non traditional options along with her current treatment for lung cancer. Joe Tippens took fennendazole while taking traditional treatment and during a study protocol. He remains NED after several years with Small Cell Ling cancer. This is now being studied as a clinical trial. Anything is worth a shot if it won’t hurt you! Even though it sounds gross “dog dewormer”. Chemotherapy is just as poisonous!

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