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

**Peter Attia, MD** (0:11)
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Now, without further delay, here's today's episode.
My guest this week is Sarah Hallberg. Sarah is a physician who has spent the better part of two decades focusing on treating patients, first with obesity and ultimately really finding her niche in type two diabetes. About 10 years ago, she became a huge believer through her clinical experience in the efficacy of carbohydrate restriction and the treatment of type two diabetes, and that led to her becoming involved in a company called Virta Health, which I'm an investor in as well, so I want to disclose that. In this podcast, we talk really about two completely separate things, each of which is important in its own right. In the first part of this podcast, we discuss the role of dietary fat and carbohydrate on the plasma makeup of fatty acid and triglyceride. In other words, does the type of fat you eat play a role in the type of fats that are found in your bloodstream? Because we have a pretty good understanding of what type of fats in your bloodstream are good and bad, how much is that impacted by what you eat? And I think for many people who are new to this area, this will be quite shocking. And suffice it to say, it's not so simple as you are what you eat. And there's enormous implication here, but I think one of the most important takeaways is that one of these fatty acids in particular, which we get into, it's a mono unsaturated fat with 16 carbons, turns out to be a very interesting early predictor of metabolic disease.
We then pivot off this admittedly somewhat nerdy discussion into perhaps one of the most emotionally riveting discussions I've ever had on the podcast, which is discussing Sarah's personal journey through the diagnosis of lung cancer. She was diagnosed with lung cancer at the end of June, 2017, as I discussed in the podcast, it was just a few days after I had seen her appearing to be completely healthy. And to say that the last four years have been anything other than difficult would be an understatement. I don't really want to say more about the second part of the podcast because I won't be doing it justice. I think ultimately it's something that frankly, everyone would benefit from listening to, and it was an admittedly difficult discussion, but one that I feel very privileged to have had with Sarah. So without further delay, please enjoy my conversation with Dr. Sarah Hallberg.
Welcome to the show. I'm super excited to be speaking with you today. This has the potential, of course, to be a 10 hour podcast, which it won't be, but I think that speaks to the depth of insight that you've got into so many topics that I actually want to talk about.

**Sarah Hallberg, D.O., M.S.** (3:35)
Thank you. It's great to be here.

**Peter Attia, MD** (3:37)
Well, in thinking long and hard about how to navigate all the threads I want to pull on, I figured we would just start with the nerdiest of all topics, which is something that I know you're so passionate about, and yet I don't think gets nearly enough attention.
And that is basically the role of dietary intake of both carbohydrate and fats and the relationship that has on the distribution of fatty acids within the body. So let me just start by asking, why is that even of interest to you?

**Sarah Hallberg, D.O., M.S.** (4:11)
Well, it's significant interest because it really hits at one of the things people criticize a low carb, high fat diet about is, oh my goodness, you'll get more fat in your muscles, in your liver, and it's gonna lead to increased insulin resistance, and thereby default going to lead to increased cardiovascular disease.
And we know that a therapeutic carbohydrate restricted diet brings down so many cardiovascular risk biomarkers that we're all used to hearing about. Okay, it decreases triglycerides. Okay, it actually can reverse type two diabetes in most cases and certainly significantly improve glycemic control in all. But fatty acids, that's not something that's talked about all that often.