Kurt G. Harris MD

PāNu means paleonutrition. The "paleo" here signifies "old" and not necessarily paleolithic. The PāNu approach to nutrition is grounded on clinical medicine and basic sciences disciplined by knowledge of evolutionary biology and paleoanthropology. The best evidence from multiple disciplines supports eating a pastoral (animal-based) diet rather than a grain-based agricultural one, while avoiding what I call the neolithic agents of disease - wheat, excess fructose and excess linoleic acid.

Support PāNu

PāNu is ad-free, completely independent and has no outside sponsorship. If you value PāNu, now you can support it. Read this for more information.

In addition to buying from the book list, you can also support PāNu by making all of your Amazon purchases for any item through the Amazon Portal below

Amazon Portal

« Where are all the healthy whole grains? | Main | The Argument Against Cereal Grains »

1) Eliminate sugar and refined carbohydrates like white flour.

Not everyone reading this makes the nutrition blogosphere rounds for the latest biochemical tidbits. Quite a few people don't yet know what “macronutrient” means, and that's OK. They are busy living their lives. I like to think one advantage of the PaNu approach is that you can be healthy without a calculator or a scale, or any doctor-provided tests whatsoever, but you do need some basic knowledge to start making choices.

Macronutrients: Proteins, Fats and Carbohydrates

Proteins are chains of smaller molecules called amino acids. Proteins are what compose our muscles and give our bones tensile strength and they include enzymes that make all the chemical reactions in our bodies possible. Generally, the body is constantly turning over proteins and re-cycling the amino acids to make new proteins for both structural and enzymatic purposes. Some of the amino acids (aas) will get used up in this turnover process, so we must have a certain amount of our calories come from protein to replenish these aas or we will literally waste away and die. There are 20 aas used by the body to synthesize new proteins, and we must have 8 of them to avoid deficiency. These are the essential amino acids we need to eat. Animal sources of protein like eggs and meat are complete sources, that is, one portion of such a food contains all eight essential amino acids. The other 12 we can synthesize from the essential 8.

Humans are omnivores and not vegetarians. Animals that exclusively eat plants are able to synthesize amino acids from a smaller essential list eating monotonous plant sources. Humans who choose to artificially emulate true herbivores by eating only plant sources must consciously mix and match different plant sources, and unless they want to eat their own feces (I am not making that up -it would take about 30% by weight), must artificially supplement to get vitamin B12 that we can otherwise only get from the animal sources we evolved to eat. Animal sources of protein like eggs and meat are complete sources of amino acids – no mix and match required to get the essentials.

Fats and oils are described by class here, but generally are in the form of triacylglycerols or triglycerides (TAGs), three fatty acids chains on a glycerol backbone. Lipid is the technical term, but lets use fats for short. The fat composition of our diets affects cell wall and other vital functions, and the ratios of fats like Omega 6 and Omega 3 has important effects on immune function and inflammation.

As a fuel, fats are nonpariel. The FDA and the AHA and the ADA and all the lipophobes say to avoid fats because they are 9 kcal/ g (versus roughly 4kcal/g for proteins and carbs) and this caloric density will somehow by itself make you gain weight. I never saw a wild animal titrate their food by weight and humans don't either. We stop eating when we are no longer hungry and nothing turns off hunger like fats. The caloric density of fat is not an accident. Animals evolved to store energy efficiently as fat, and humans evolved to eat the the fat that prey animals we co-evolved with have stored “on our behalf”. We store the majority of the extra energy in our own bodies, whether derived from fats or sugars or proteins, as fat, especially saturated fat. To suspect that the saturated fat we store in our own bodies in such large amounts causes disease is wholly implausible, and I have yet to see any convincing scientific evidence that it does. Animal fats are quite simply the anchor food source of the PaNu approach.

Carbohydrates are simple sugars (glucose, fructose, etc..) or polymers (long chains) of simple sugars called starches. Glucose and Fructose are simple sugars. One glucose joined to one fructose is one sucrose disaccharide molecule. Sucrose and high fructose corn syrup or HFCS (manufactured from corn) are metabolically equivalent for all practical purposes. They are equally bad for you. Sugars can be burned as fuel or converted into storage fat in our bodies. They have other biological functions within the body, but importantly, there is no such thing as an essential carbohydrate. Any sugar or starch needed internally can be synthesized from scratch. Unlike the case with Proteins and Fats, starches and sugars are basically just fuel. PaNu theory (well, basic cell biology, actually) recognizes that sugars are the oldest cell fuel. Many bacteria and primitive organisms, and dedifferentiated cancer cells, can only use glucose (sugar) as fuel. During the long evolution of animals, the ability to store and use fatty acids evolved as well. This has had huge advantages in energy storage and efficiency for animals. It is my working hypothesis that during much of human evolution, fatty acids were a much more utilized fuel source within the human body, and even though it was adaptive during our evolution for humans to exploit carbohydrate rich food sources when in a food scarce environment, our current food abundant environment has us using glucose as an internal fuel far more than what we are biologically adapted to. This is the first central dogma, if you will, of PaNu theory. Lets state this central dogma for reinforcement:

I. The first core departure from the evolutionary metabolic milieu (EM2) is the degree to which we use glucose as an internal fuel relative to fatty acids.

In a food abundant environment, where there is no caloric deficit, carbohydrates as a large fraction of caloric intake create a situation where our metabolism is not spending enough time in or near the fat-burning state known as ketosis. The consequence of this is the metabolic syndrome, which is insulin resistance, diabetes, hypertension, obesity and a variety of other diseases that have highly suggestive lines of evidence connecting them to chronically increased levels of insulin and/or serum glucose – including coronary artery disease, deep venous thrombosis, pulmonary embolism, atrial fibrillation, atherosclerosis, alzheimer dementia, degenerative diseases and even the most common cancers like breast, colon, lung and prostate.

Now, as a physician who sees a wide variety of ailments in the context of people who are ill enough to need MRIs, CT scans and Ultrasounds, I can tell you that this short list is about 60% or more of the serious diseases that I encounter routinely. Imagine if these diseases of civilization were not an inevitable consequence of aging, each with a different cause, but were all a consequence of living long enough despite eating the wrong diet – a diet that deviates from the EM2. That is what I believe to be the case.

My first central dogma is just a subtle extension of Gary Taubes' carbohydrate hypothesis. For the comprehensive tour-de-force argument for the carbohydrate hypothesis, read Good Calories, Bad Calories by Gary Taubes

So what can we do to get closer to the fat-burning metabolism of the EM2?

Let's look at our current diet (not yours or mine, the average north american's) and see what it's macronutrient composition is. (These figures are approximate but pretty close)

Average daily calories 2300

Sugar and HFCS 100 lbs/yr 496 kcal/day per capita = 22% Source – HFCS web site

Flour 138 lbs/yr 685 kcal/day per capita = 30% Source - The Wheat Foods Council

The percentage figures as a fraction of daily calories are 22% Sugar and HFCS and 30% from wheat flour.

These figures may be high and count wastage and protein (gluten), so lets round the flour carbs down to 20%. Most figures for current total carb consumption are 55%. So, being generous, we can ballpark all other sources of carbs like vegetables and corn and rice and fruit, etc. at 15% of calories.

So we have, roughly, 22% sugar and HFCS, 20% flour carbs, 15% veggie carbs, 16% protein and 27% fat.

Note that all the vitamins, and all of the essential aas and fatty acids (if we are getting them) are coming from 58% of our diet.

To get closer to the fat burning metabolism of the EM2, what can we do with this as a starting point?

Insulin levels can be low despite a high carbohydrate fraction and we are in ketosis if we are in constant caloric deficit, but this has nasty side effects like lethargy, muscle wastage and well, eventual death if we keep it up. Being hungry all the time is no fun either.

How about eating 55% carbs and only eating every other day, a rigorous form of intermittent fasting? Well, there is some evidence that would work, but I would not prefer alternate day eating to once or twice a day, and try fasting 24 hours after big plates of pasta sometime. Good luck with that.

Perhaps we could agree that Sucrose, HFCS and white flour are providing absolutely nothing essential to our diets, and the sugars (they are all nothing but sugars with some gluten protein in the flour) are just stimulating insulin secretion (glucose) and if not stimulating insulin, they are being converted directly to fat, damaging our liver, and making us eat more by not shutting off our appetites (fructose). To make our cells more reliant on fatty acids and avoid the damage from too much sugar in the diet and the bloodstream, we will completely eliminate 42% of our diet. That is step 1 of PaNu.

Now we have a 42% hole in our diet. We can fill it with more macronutrients from the following:

a) 15% other carbs category choosing from starchy foods like corn, rice, potatoes or fructose laden fruit.

b) 15% other carbs but choosing non-starchy vegetables like green salads, broccoli, asparagus etc.

c) Protein 16%

d) Fats 27% (This number has actually decreased at the same time obesity has increased over the past 20 years)

The a) choices just add back glucose and fructose we just removed even if we picked up a few vitamins from sugary fruit. The b) choices might be OK, but if you avoid starch and add green vegetables till they are over 60% of calories you have added most of the carbs right back and you are now chewing for hours a day like a chimpanzee just to get nourishment. * 

Now, people don't eat pure macronutrients once they've eliminated sugars and flour. They eat foods that are composed of macronutrients. We need lower the carbohydrate fraction by adding back foods that don't just raise it back again. Since Fats have zero insulin response, are a great fuel source, and give great satiety, why not do this:

Increase Fats to 65-70%, and cut out all residual grains, legumes, and starchy vegetables like potatoes, corn and rice so that only the green salads and non starchy veggies are left. This will get carbs down to 10% (roughly 50g per day) and absolutely minimize glucose, fructose and insulin effects. For the reasons elucidated here we will not allow mechanically extracted seed oils into the diet. This leaves animal sources like butter, cream and flesh of animals like beef, chicken, pork and fish. Now, when we seek out these natural unprocessed animal sources of fat, we will get a bit more animal protein and many more vitamins in the bargain.

Keep carbs around 10%, seek out animal fats, let protein come along for the ride and you will get close to these ratios, + or – 5% for each:

65-70% Fat, 20-25% Protein, and 10% carbohydrates.

This may well be more protein than you need.

No harm reducing it to 15% and adding more cream  or butter

Try it. Record everything you eat for a few days while sticking to 1 through 4.

Use Fitday to calculate your ratios. It will be hard to radically deviate from the above ratios unless you purposefully try to subvert it.

Now is when you ( well not you, but those who buy the healthy  grains propaganda) say:

Where are the healthy grains?

Answer in the next post.


*Greens are fibrous and not starchy or calorie dense, so if we add enough back to replace the lost calories, we are eating a huge amount of vegetables now. This is in fact advocated by authors like Colin Campbell and Joel Furhman - it can have some effect as the mechanical satiety and sheer work of eating may reduce your caloric intake. However, you will be having a minimal effect on insulin levels at the expense of eating fewer higher quality animal foods and absurd amounts of fiber - this approach only makes sense if you think animal products and fats per se are unhealthy - they are not. Also you just don't need that many vegetables in general and you don't need "fiber" at all.


Reader Comments (22)

Hi Dr.,

I decided to give low-carb diet a try in attempting to solve my reflux (GERD) problems.
So no more starches, pizza, bread, pasta, potatoes.
It worked, but...

I loose 18 lbs. in some weeks.
As I'm now very thin (119 lbs for 5.8 ft.) this is not a great thing.

If my calories need was 2300 calories, and if I had to follow a high-fat low-carb diet without grains and starches (65-70% fat), that means I'd have to eat 166 grams of fat.

How could I eat that huge amount of fat? I cannot take bites out of butter or drink a quarter of a glass of olive oil...

Keep in mind I like low-carb diet, I'm merely saying it's not possible to avoid to loose many many lbs. of body weight when on it... and in my case it's not a good thing.

Any suggestion to avoid this?



June 28, 2009 | Unregistered CommenterMarco

Why not switch to (grass fed if you can afford it) steak instead of lean meats? And yes, you can eat butter. I do!

June 28, 2009 | Unregistered CommenterJeremy

Hello Marco

Have a large cup of coffee with 5 tablespoons (75 ml) whole cream twice a day - 500 kcal/day fat

Cook everything in butter and butter your vegetables liberally - 1/3 stick of butter - 500 kcal/day fat

Have half a bar of Lindt 85% chocolate - 200 calories from fat (only 10g of carbs)

That is 1200/2300 or 52% calories from fat, not counting everything else you ate that day

It's really pretty easy.

You could eat a stick of butter like an ice cream cone, I suppose, but I've never tried it.

June 28, 2009 | Registered CommenterKurt G. Harris MD


Could you explain why there is a difference between processed and unprocessed carbs? It's often said for example that brown rice is better than white rice because it is digested slower so there is not as much of an insulin rush. (I realize you wouldn't necessarily recommend brown rice at all.) But...if it takes twice as long to digest, and the insulin released immediately is half as much at first, does it last for twice as long? Why is that better?

Enjoying the blog so far!



June 28, 2009 | Unregistered CommenterAndrew


You are on the right track to why I completely eliminate grains and Step one is just the first step

without jumping the gun too much - the answer is mostly bioavailability, and my whole argument is that there is not enough difference to really make a difference in a food abundant environment.

June 28, 2009 | Unregistered CommenterKurt G. Harris Md

Dr. Harris-

Finally! Someone else who agrees the dark chocolate kicks butt over the rice!

Honestly, love your blog so far. Seems like you and Peter from Hyperlipid are largely on the same page. Would you agree?



June 28, 2009 | Unregistered CommenterCraig

Hi Craig

Yes, it's a bit uncanny. I only saw Peter's blog for the first time about two months ago. I was a bit worried he might think I was a plagiarist, but there are Darwins and Wallaces all over this fat good/ carbs bad paradigm shift.

I can recommend Peter's blog highly.

That we arrived at the same place - one from clinical medicine and one from research biochemistry - should only
reinforce our confidence that the ideas have merit.

June 28, 2009 | Registered CommenterKurt G. Harris MD

marco -

it is possible to eat above 200g of healthy fat per day. I add fat to everything I eat. coconut milk with coffee, eggs with bacon grease, butter and olive oil and cheese with vegetables, cream with fruit. fry foods in lard or coconut oil or ghee. snack on almonds, walnuts, mac nuts, etc. you get the idea.

June 28, 2009 | Unregistered Commenterjon w


I totally agree and understand that it is important to get enough healthy fats, and to avoid carbs and grains. But I have a question on dairy fats. The last step of getting panu is getting rid of milk. Does that also mean eliminating butter, and cream?



June 29, 2009 | Unregistered CommenterPieter


Elaborating on my previous question (see above), and after rereading your post on dairy and the casein protein in them, I think I can guess the answer to my own question.

But it lead to another one... Since a few years a have very mild symptoms of psoriasis, which are easily supressed with a little bit of cortisone ointment once in a while. Since psoriasis is an auto-immune disease, I was wondering if there is some kind of test (other than trying to eliminate dairy) to know whether I'm sensitive to those casein proteins? And is there a test to know whether one is sensitive to the grain proteins causing the leaky gut?

I've been experiencing a bit with the diet and haven't noticed any change in the psoriasis (I've noticed some other great changes though!).

Thanks for your thoughts,


June 29, 2009 | Unregistered CommenterPieter


I will talk about Gluten avoidance and sensitivity in my next post.
Are you already gluten fee and if so for how long?

June 29, 2009 | Unregistered CommenterKurt G. Harris MD


I'm not really counting, but I guess I'm something like 95% gluten free. I don't eat grains of grain deriven products. I almost only eat things made from fresh plants, meat, fish and eggs. I avoid (nearly 100%) of eating 'fabricated' meals. But occasionnally I eat a liitle piece of bread, a few corn pieces in a mixed salad, ...

I've been eating for this the last three months. the 4 months before that I would guess it was more like 80%. Before that I ate healthy, but in the 'conventional' way: many fruits and veggies, some meat and fish, not much fat and quite a lot of carbs (potatoes, rice, grains, bread, pasta), although almost no extra sugars...



June 29, 2009 | Unregistered CommenterPieter


The reason I asked is that the antibody tests for gluten sensitivity become less useful once you have spent several months gluten free.
It sound like you are most of the way there already, why not go all the way?

If the psoriasis is leaky-gut-related, it may take a while for your immune system to "cool down" - offhand, my clinical experience is that allergic rhinitis can start to improve days into a grain reduced diet, but more serious autoimmune diseases may take years to go away even if completely grain-free, and some unfortunately might not go away once started.

I would give the psoriasis some time. If you are 100% gluten and legume free for months and it is not improved, you might try casein elimination too - this would allow you whole cream and ghee (clarified butter fat), but otherwise no dairy.

Also, get out in the sun - UVB is a great treatment for psoriasis and boosts your vitamin D levels as well

I'll post much more about these issues soon.

June 29, 2009 | Registered CommenterKurt G. Harris MD


Thank you so much for the advice. Fortunately, as I mentioned, the symptoms are rather limited, and now knowing that the diet can need some time, I will continue...

Indeed, the sun is great. Unfortunately I live in one of the richest countries, but it is very poor in sunshine... I live in Belgium. But the weather is great now.

Looking forward to more of your posts,


June 29, 2009 | Unregistered CommenterPieter


I've been a fan of hypelipid for a little while and just came across yours last week - linked from Mark Sissons Primal blog. I roughly follow your macronutrient ratios already, if not closer to Optimal Diet (80% fat). Having experience of this, I aim for between 40 - 60g of carbs a day, and I'm curious how you reach that whilst cutting out all starches (and sugars - though I note the inclusion of Lindt above, I eat dark chocolate too).
Can green veg add up to 50g of carbs?


June 30, 2009 | Unregistered CommenterDavid

re: can green vegetables add up to 50g of carb? i've just started adjusting my food intake and started tracking using fitday. i have a large salad at lunch- romaine, broccoli [raw], sweet red pepper, grape tomatoes, a handful of walnuts, some olive oil and balsamic vinegar. that adds up to 36g of carb - in a lunch salad - with almost equal contributions of 7-9g each from the broccoli, pepper and tomatoes, and around 4g each from the romaine, walnuts and vinegar. add a couple of veggies at dinner and you get to 50 easily.

June 30, 2009 | Unregistered Commenterjeff klugman

David, I don't count or measure. The carb fraction comes along for the ride. It is not like a vitamin where I try to get at 50 g a day. Some days it's near zero, some days it approaches 100g. Depends mostly on how much whole milk (my version of fast food) I drink. Also see Jeff's response below

Hi Jeff

This is what is great about no grains - eat that green salad twice a day and you are still at only 76 g total cabs and getting more micronutrients
than a carb-equivalent amount of fruit or grains would provide.I n fact if the core of your diet is animal based- you can go ad libitum with the greens, never count or weigh anything, and almost never be above 100-125 g of carbs daily. Not suggesting that, just pointing it out.


June 30, 2009 | Registered CommenterKurt G. Harris MD


"you don't need "fiber" at all."

Could you please give some references? I heard that position, but I cant find suitable reference. So far, fiber is said to be very important for the digestive system.



July 3, 2009 | Unregistered CommenterMiguel Angel

Hi MIguel

Observational studies have shown "associations" between fiber intake and health indices - these are confounded by other variables like sugar consumption, however.

Intervention trials have failed to show any benefit whatsoever to having indigestible carbohydrates (fiber) in your diet.

The idea originated with Burkitt but most of his original observations are much better explained by carbohydrates (as Cleave and Yudkin pointed out).

More on fiber in the future. Read GCBC by Taubes in the meantime- he gives a good discussion of this.

July 3, 2009 | Registered CommenterKurt G. Harris MD


Enterolab has gluten and casein sensitivity tests that may meet your needs.

July 14, 2009 | Unregistered CommenterEGK


I have a question about fiber. Your comment that fiber is not necessary seems credible because I've read that the Alaskan Inuit ate only meat and no plant based food. They were healthy and their consumption of fiber was zero. About 10 years ago for a short period I tried the diet plan popularized by Dr. Atkins which consisted of very little plant based food and mostly meat. I had never had trouble with constipation in my life, but after a while on this diet it was like concrete in my bowels. In my own experience I found that at least a small amount of fiber was necessary. Do you think that it's a matter of adaptation? Would it be that a person could have to get used to having no fiber? Thanks. I'm enjoying your site.


August 15, 2009 | Unregistered CommenterMike

Dr Harris,
Thanks for putting together your excellent blog and the information it contains.

I've seen many references on various blogs/webpages stating that cancer cells pretty much solely depend on glycolysis for survival. I'm trying to understand an article by Dr Ray Peat that 'seems' to say otherwise - I probably don't have enough knowledge of biochemistry to actually understand it. Would you be so kind as to look the article over when you get a chance, and share with us what the practical response to it would be? It sounds like it is important within an EM2 frame of reference. If so, it is at

KGH: No time to debunk Ray "fructose is safer than glucose" Peat. Read with caution.

November 18, 2009 | Unregistered CommenterJim
Comments for this entry have been disabled. Additional comments may not be added to this entry at this time.