The Ketogenic Diet and Peter Attia’s War on Insulin


Being a marathon runner with type 1 diabetes is tricky business.  Normally, I eat a very low-carb diet which helps me maintain fairly stable blood sugar.  But before a long run, I need to have enough fuel for energy, but not so much that my blood sugar gets out of control.  Because this balance is so hard to achieve, I’ve found carbo-loading to be the most difficult part of my long-distance running experience.  I’m always looking for a better way to do it.  It turns out, there may be one.  Thanks to Peter Attia’s new blog, The War on Insulin, I’m learning all about the ketogenic diet.

Peter Attia was born and raised in Toronto, Canada. He studied mechanical engineering and applied mathematics as an undergrad at Queen’s University. Shortly before starting his Ph.D. in aerospace engineering, a profound personal experience led him to medical school.  At Stanford Medical School, Peter believed he would become a pediatric oncologist, but by the time he started his clinical rotations he realized surgery was his passion.  Peter did his residency in general surgery at the Johns Hopkins Hospital in Baltimore, Maryland and while there spent two years at the National Institutes of Health (NIH) in the National Cancer Institute as a surgical oncology fellow.

About six years ago, Peter became frustrated with certain aspects of medicine and health care, in general. In particular, he grew tired of the notion that doctors did little to keep patients healthy, and were basically the last line of defense against death once patients became ill. With the concept of “preventative medicine” on his mind, and missing quantitative and analytical problem solving, Peter left medicine to join the consulting firm McKinsey & Company. Today Peter is working full-time on his passions around nutrition and nutrition science, including writing, coaching, and starting a non-profit organization.

Following in the footsteps of Good Calories, Bad Calories’ author, Gary Taubes, Peter is challenging all that we’ve been taught to believe about the interaction of health, human performance, and medicine. Peter wants to demonstrate that insulin and the foods that stimulate insulin, not excess calories, are at the heart of the most pervasive chronic diseases: obesity, type 2 diabetes, heart disease, and even cancer. Suppressing the secretion of insulin, he says, is the key to running your body on your own fat, which leads not only to weight loss, but also to what he calls “chronic health.”

Peter follows what’s known as the ketogenic diet, which was originally developed to treat pediatric epilepsy in the 1920s.  The ketogenic diet is a high fat, moderate protein, low-carb diet. For those of us with type 1 diabetes, when we hear something that sounds like ketones are involved, there’s a good reason to be wary.  One of the life-threatening risks of type 1 diabetes, after all, is diabetic ketoacidosis, or DKA, a condition which results from a shortage of insulin.  But there is a big difference between DKA and the ketogenic diet.  DKA happens in the absence of insulin.  Even if there is a large amount of sugar in a person’s body, without insulin, the body’s cells can’t use it, so the body is effectively in a state of starvation.  In response, the body switches to burning fatty acids for fuel and thereby produces ketones.  In nutritional ketosis, or keto-adaptation, as long as insulin is present, there is no such risk.

On the ketogenic diet, a person’s body begins to burn and utilize fat for energy through significant reduction of carbohydrate intake (typically to less than 50 grams per day).  This means the body changes from relying on glycogen as its main source of energy.  In particular, in a keto-adapted state, the brain shifts from a sole dependency on glucose to a state where it can also acquire energy from a by-product of fat, called beta-hydroxybutyrate.

Peter consumes about 4,000 to 4,500 calories per day on average. (He exercises a lot!)  His calories come from approximately 400-425 grams of fat, 120-140 grams of protein, and 30-50 grams of carbs.  In addition, there are a number of supplements he takes.

I had the great opportunity to talk to Peter and find out more about the ketogenic diet he follows and a few other topics.

Do you eat any complex carbs? 

That depends how you define complex carbs and my motivation for eating them.  I consume salad, not because the lettuce is good for me, per se, but because I consider it a “conveyer belt” for fat ingestion.  For example, I actually had 2 salads yesterday – one for lunch and one for dinner.  I make my own dressing, even when at a restaurant, as it’s a great way for me to consume a lot of fat, but control exactly which fats.  I’m pretty particular about not eating too much omega-6 fats, what I call “junk oils.”  I don’t really eat any fruit or other vegetables with great regularity.  I sauté onions and mushrooms once in a while, but mostly that’s just another way to eat lots of fat, such as butter and coconut oil.

No greens?  Leafy greens?  Broccoli? 

I eat them a little bit, of course, but at the end of the day I’m really focusing on eating a higher quantity of fat.  The reality of it is that I probably still eat more vegetables in that category than the average person, but nowhere near what I used to eat.  I used to eat a lot of fruits and vegetables and complex carbohydrates, kind of the iconic athlete’s diet, where about 65% of my intake was coming from those products.

So no pasta, rice, corn?

I view those foods the way I view cigarettes.  Literally.  I’m totally starch-free.  And obviously I consume no sugar.

You exercise a tremendous amount.  How do you fill the stores of glycogen in your muscles?

It’s a pretty big misconception that you can’t have or produce glycogen on a ketotic diet.  On Sunday, for example, I went for a five-and-half hour 90 mile (150 km) bike ride at pretty high intensity with 9,000 feet (2,800 m) of climbing.  In the morning I had bacon, eggs, and whipping (heavy) cream in my coffee.  A ride like that burns about 4,500 calories, but during the ride I only ingested about 50 grams of something called superstarch (about 180 calories worth) and about 2 ounces of mixed nuts (approximately 300 to 350 calories).  In other words, I was able to supply my muscles with sufficient energy from existing fat stores and existing glycogen stores, depending on the level of intensity.

When fully loaded you store about 1,600 calories worth of glycogen.  The real point to keep in mind is that it’s more about your ability to access your fat stores than your glycogen stores.  If you’re solely reliant on your glycogen stores, you get into trouble really soon because you’re going to deplete those stores.  You’re going to constantly need to replace glucose during the exercise.

Could someone with type 1 diabetes follow your diet?

Let’s start with type 2 diabetes.  The single most important thing for type 2 diabetics is carbohydrate restriction.  It’s been demonstrated in as many clinical trials as I could possibly count.  In fact, most type 2 diabetics can be off of insulin within 2-6 weeks of restricting carbohydrates.   I’ve worked with type 2 diabetics who went from needing 180 units of insulin per day to requiring zero insulin within 4 weeks.  And they feel infinitely better, their risk of heart disease goes down, and they lose body fat.

I also know, and have worked with, a number of type 1 diabetics and it is also the case that you can reduce significantly their insulin requirement when you reduce the amount of carbohydrate they’re consuming.  One of my closest friends from residency is a cardiac surgeon who’s been a very well-controlled type 1 diabetic for 16 years.  He was able to reduce his need for insulin — both basal and bolus — by about 80%.  Another colleague of mine has type 1 diabetes and required 200-250 units of insulin a day and within a month of significant carbohydrate restriction she was able to reduce that to about 20 units a day.

What’s really important to say here is that anyone with diabetes, especially type 1 diabetes, needs to work closely with their physician.  I’d also recommend a book by Richard Bernstein, a physician who himself is a type 1 diabetic.  While it’s certainly not “mainstream,” I really believe carbohydrate restriction is important for both type 1 and type 2 diabetes.  Let me give you an analogy: When I hear a physician saying to a type 1 diabetes patient, “Go ahead and eat whatever you want, just make sure you cover your glucose with insulin,” it’s like telling a firefighter, “Just go ahead and pour as much gasoline as you like on that fire you’re trying to put out, as long as you cover it with enough water.”   Completely circular and illogical.

How much fat a day do you eat?

Fat, for me, makes up 85-90% of my calories, but this is because I consume so many calories per day.  For many folks in nutritional ketosis, fat makes up 65-75% of total calories.

 What about good versus bad fats?  Are all fats equal?

What I consider good and bad is different from what most would consider “good” and “bad.”  Most people, including myself, who come from a traditional medical background are led to believe that saturated fat is the “bad” fat.  But the reality of it is this – there’s really not a shred of meaningful scientific evidence to even suggest, let alone demonstrate, that saturated fat is bad for you.  If you’re really interested in understanding this topic, a great place to start is reading Gary Taubes’ book Why We Get Fat, and if you want the more detailed version you should read Good Calories, Bad Calories.  Unfortunately, it takes a while and a lot of reading to “undo” the bad habit bestowed upon us.

The story around saturated fat has to do with some very poor epidemiology between the 1950s and the 1980s that led to a number of health policy changes in the U.S. that were unfortunately not grounded in meaningful and accurate science at all. Interesting observations, yes, but poor conclusions. In fact, a number of scientific reviews over the past five years have acknowledged that despite everything we’ve been told about the harm of saturated fat, there’s actually no evidence that saturated fat is harmful.  The nuance is this – having saturated triglycerides in your blood is predictive of heart disease.  But there’s no association between the saturated triglycerides you consume and what ends up in your bloodstream, let along your arteries.  In fact, the consumption of simple carbohydrates and sugars is what leads to the presence of elevated triglycerides in your bloodstream, including saturated triglycerides.  The same is true for cholesterol.  There’s been a lot made in the past about eating too much cholesterol, but what most people don’t realize is that the cholesterol you eat, which we call exogenous cholesterol, has no bearing on the cholesterol in your bloodstream.  The cholesterol that ends up in your bloodstream is produced by your own liver, which we call endogenous cholesterol.

The fat that I do consider bad is omega-6 polyunsaturated fat (e.g., plant oils like soy, canola, sunflower, safflower).  The ratio of omega-6 to omega-3 fats one consumes plays a large role in helping mediate inflammation in your body.

People often ask why, historically, some cultures stayed lean while consuming starch, like the Japanese, French, and Italians.  They ate starch, and didn’t gain weight, and don’t have the obesity epidemic that we have in the U.S. (yet).  Of course, this is no longer true, as these cultures are doing their best work to catch up to U.S. rates of obesity, diabetes, and the cluster of diseases that stem from these, but historically this was the case.


Three reasons, in my mind.  First, they didn’t consume a lot of sugar – in fact, at the peak of their health they consumed probably less 10% of what we consume today in sugar as a nation.  Second, they didn’t consume a lot of glucose at any one time – even though the ratio foods they ate were high in carbohydrates, their actual glycemic load was quite low.  Third, their ratio of omega-3 and omega-6 fats was largely in balance.   Asian and Mediterranean cultures consumed abundant fish (omega-3) and so little junk oils (omega-6) that they were always in a perfect balance, between 1:1 and 3:1 (omega-6 to omega-3).  In the U.S. the average person is consuming 30-60 times more omega-6 than omega-3 fats!

So, I eat a lot of fat, but I profoundly restrict my intake of omega-6 fats.

Do you consume artificial sweeteners?

Short answer, yes, but not that much.  There’s no actual evidence that artificial sweeteners are harmful to humans.  Aspartame has probably been tested more than any substance humans have ever ingested, and it’s been around for over 40 years.  There’s never been a piece of evidence to suggest that in humans it’s harmful.  In an animal model you can make anything happen, of course, especially when you feed an animal an amount of something a human could never consume.  We don’t have as much data with a lot of the other substitute sweeteners, but all the data available suggest these substances are safe – certainly safer than sugar.  I’ve actually written a blog post about this exact topic, and I’ll publish it in 2 or 3 weeks.

To cut to the chase, if your choice is between drinking a Diet Coke sweetened with aspartame or a regular Coke sweetened with sucrose or high fructose corn syrup, there’s no comparison as to which one is more harmful – the regular Coke.

I don’t consume a large amount of non-sugar substitute sweeteners.  You’d be amazed at how quickly you can lose your taste for sweet once you get out of the vicious cycle.

You follow a really strict diet, and so do I.  But do you believe most people could do this?

I absolutely do.  Why do people eat what they eat today?  Two reasons – first, bad information, second, poor food infrastructure.  People have been brainwashed into thinking that certain foods are “good” and certain food are “bad.”  Secondly, we live in world where we have food-based policies and food infrastructures that makes it very easy to eat a certain way, which is unfortunately the wrong way.  You do, initially, have to go out of your way to avoid the foods that make you unhealthy.   They are just so ubiquitous.  Over time, and with improved understanding, it becomes easier and easier to ignore the “bad” foods.

For me to eat the way I do is not difficult at all.  It’s trivial, actually.  I travel constantly and I can eat my ketotic diet whether I’m in a hotel, at home, or in an airport.  What matters is that I know what to eat and what not to eat.  It’s not actually about, “do eat this, don’t eat that,” though I realize at the outset that’s what it appears to be.  It’s about understanding how what I put in my mouth impacts the hormones in my body.  It takes a while to understand this interaction, but how many things of great value can you learn in ten minutes, or on a bumper sticker?

If you really want to do something to change your life and make a huge impact, you’ve got to actually understand why you’re doing it.  And I’ve worked with countless people who have been able to – over a period of months – change the way they eat in such a way that if they had looked at it from the outset they would have said, “I’d never eat that way because it seems too much a series of rules and restrictions.”  But in the end it becomes very easy.

Another point I’m really passionate about is the not-for-profit initiative that Gary Taubes and I are putting together, the Nutrition Science Initiative, or NuSI, which we hope to launch this spring.  One of our hopes is to get policy makers to revisit the question of what does and what does not constitute a healthy diet.   In other words, though revisiting the science of this field, the other way to tackle this problem is from the food infrastructure and policy side.

Do you believe there will there be a change in mainstream American food thought?

I do, and I’m willing to devote the rest of my life to helping others make this happen.

For more on Peter Attia and the ketogenic diet, visit his blog The War on Insulin.

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Tara Anne Tyler
Tara Anne Tyler
5 years ago

Perhaps you can direct me to this answer. I am T1D female for 35 yrs and have high LDL cholesterol. I have been eating mostly low carb/ketogentic for the last two years. I am an RN and have a good understanding of physiology. My MD wants me on a cholesterol lowering med, but I’m not convinced I need this. I eat 1-2 avocados daily, coconut cream and butter. Any help would be appreciated. My labs are as follows:
Total Cholesterol: 269 (High)
Triglycerides: 47
HDL: 85
LDL: 175 (high)
9 years ago

This is a letter to my 17 year old daughter after I have just watched several informative videos on the ketogenic diet: Alex – When I sat there with you on two occasions and listened to “health care professionals” telling you “Go ahead and eat whatever you want, just make sure you cover your glucose with insulin,” and make claims that “your body and brain cannot function without carbohydrates – you will die”.  I was furious because, although I was too ignorant at the time to speak up and take a stand on this topic – due to my ignorance, in… Read more »

9 years ago

I am the mother of a type 1 diabetic, she is 15. She is extremely dismissive of the fact that she has diabetes and we cannot get her blood sugar under 200 most of the time. I would like to get her started on a ketogenic diet to try and bring down her A1C and balance her blood sugar levels, but I am worried about DKA. Anyone have any tips on how to begin the diet and how to thwart DKA from the start? Any info will be appreciated. 

10 years ago

Haven’t seen a response to your question on the site, but I am a type 1 diabetic and biker and can recommend a great book by Jeff Volek and Steve Phinney (both Drs) called “The Art and Science of Low Carbohydrate Living”. They have done some important work studying the effects of a low carb diet on athletes. I am slowly moving towards a lower carb diet, but have not fully embraced it yet. Peter Attia’s website “The Eating Academy” is also very helpful and discussed low carb diets and exercise as well.
Good luck to you.

10 years ago

Hi Michael,

I am a type 1 diabetic (on insulin pump) and also a runner hoping to compete in a few 25k trail races this year. I run about 65-70k a week. I am quite interested in the ketogenic diet, but worry about what to eat and when to sustain my training (I run from 6-7:30am before breakfast having fasted through the night … and definitely have a bit of dawn phenomenon so don’t have to worry about going low during the run). Could you recommend some resources for getting started on such a diet? Thanks.  

Lars Schroeder
Lars Schroeder
10 years ago

Dear Dr. Attia, I saw you on Stossel tonight. I was so glad to hear someone else proclaiming that all calories are not equal. I am 57 years old and have been on Dr. Barry Sears’ (M.I.T.) “Zone Diet” for 15 years. I am about 4 pounds heavier (160) than I was in my high school sophomore year. I am a runner and do long distance. I credit my excellent health (not been sick in many years) and unbounding energy to my diet. Dr. Sears’ research and assertion that insulin levels make or break good health is worth your time to look… Read more »

11 years ago

I completely agree with these viewpoints. I have personally lived on the low-fat high carb diet for almost 30 years and yet kept gaining weight and had a completely screwed up lipid profile. The Dr. almost put me on statins and thats when I decided to take matters in my own hands and started investigating exercise and good fats for heart health. I was of course shocked to not find a single piece of evidence that correlated dietary cholesterol to lipid cholesterol. I then started investigating saturated fats and still couldn’t find any evidence that saturated fat will cause heart attacks. I… Read more »

Michelle S
Michelle S
11 years ago

what an interesting article. thank you from a fellow Canadian!  I think we definitely need more people to question the conventional way of thinking about food and disease.  I admit i struggle with the idea that bacon and whipping cream can be okay for us…. especially given what most animals who are consumed (mainly from factory farms) are fed and how they are treated.  A true caveman diet many moons ago would have been on organic meats.   However, I do think calorie restriction leads to living longer and I guess we need very long term longitudinal studies to know… Read more »

Sally Roman
11 years ago

We have two type 1 diabetic sons that we have had on a therapeutic ketogenic diet for about 4 years now.  They are doing incredibly well.  You can read their story on our website:
It is wonderful that Peter is encouraging people with Type 1 Diabetes that diet really does matter. 

Rich Murray
11 years ago

I find it fascinating — scientific evidence to support the polar opposite of the John McDougall low fat and protein, high complex starch, low sugar, plant only diet, without chemicals — are there major differences in genetic patterns?   Re aspartame and modern diseases of civilization: methanol from tobacco and aspartame is made into formaldehyde inside human cells by ADH enzyme, While Science Sleeps, WC Monte Woodrow C. Monte at his site WhileScienceSleeps now offers affordable $ 10 Kindle electronic 250 page book that links to 740 free full text mainstream scientific papers — giving specific… Read more »

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