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.

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6) Intermittent fasting and infrequent meals (2 meals a day)

EDIT 1/8/2010: Step 6 used to be intermittent fasting. I now view IF as a useful fat loss technique, and no longer see it as necessary to achieve the EM2. Ketosis may prove to be therapeutically useful ( already is for brain degenerative disorders) for cancer prevention or treatment, but I do not think being in ketosis or frequent IF is necessary to be healthy generally. I still believe in the practical advantages of using animal fats as a fuel source.


Step 6 is a cultural counterweight to all the stupid advice you see about "frequent healthy snacks" in the mainstream media. We are told to eat frequent snacks because the standard american diet with 55% carbs has you metabolically and emotionally tethered to frequent boluses of glucose.

Go watch a kid's soccer game- they can't play for 15 minutes without a break for cookies or corn-syrup-laden juice boxes or gatorade - our children are sugar junkies and the advice to eat frequently is just advice to not stray too far from your dealer so you can get a fix when your blood sugar starts to crash!

So I agree with Gary Taubes that we should listen to our bodies, but only after we have kicked the cocaine, the alcohol, the cigarettes the sugar, and the cereals.

Otherwise our bodies are likely to tell us we need something that is not good for us.

My experience has been that without the frantic hunger of a glucose-eater, I can eat at whatever time is convenient. I eat the right types of foods, with no measurement, counting or weighing whatsoever, and I stop eating when I am satisfied. My weight has been absolutely stable eating this way for almost 2 years, putting the lie to the idea that you need to "count calories' to keep weight off. Our weights and appetites are under hormonal control, and our bodies regulate them quite precisely at given macronutrient ratios and the hormone levels that result.

I began to fast spontaneously a few months into eating low carb (my percentages are about 65% fat, 25% protein and 10% carbs). On LC, the character of hunger changes completely. Without swings in blood glucose, and with cellular adaptation towards fatty acid metabolism, the "sick' sort of hunger that most people think of as hunger goes away. I find that I can arbitrarily fast for up to 18 hours with no discomfort whatsoever. If the goal is to keep your insulin levels low, it is only logical that increased intervals between meals increases the amount of time spent in the fatty-acid-fueled state, and less in the pro-inflammatory, oxidative stress-causing state where your body is trying to deal with excess calories, especially from glucose. I believe intermittent fasting and infrequent meals decrease the hormonal signals that lead to disease and the hormone sensitive degenerative diseases that we think of as "aging".

Advantages of infrequent meals:

1) Enhanced metabolic training in the direction of fat metabolism

2) Lower insulin levels and fewer insulin related diseases (Metabolic syndrome, degenerative diseases, Alzheimer's, common cancers)

3) Greater tolerance for fasting makes it easier to tolerate not eating - this give you "metabolic headroom" -it makes you more functional and resilient - You are a Porsche with a 40 gallon gas tank instead of a truck running on lead acid batteries.

4) If you exercise while fasting, the lack of insulin in the fasting state improves the fat-mobilizing and insulin-sensitizing benefits of the exercise.

I eat around noon and again about 9 pm most days. So every 24 hours has a 15 hour fast and once in a while up to 18 hours. Please understand that this is in no way uncomfortable and my weight has been stable at 157-158 lbs for over year. It's not some kind of deprivation or an ascetic experience. I have no idea if this is better than 3 meals a day with a 24 hour fast once a week. This is just what I do spontaneously, but my reading of the literature backs it up as beneficial.

I am sure my regime is healthier than the 5 meals a day "The Zone" or other pseudoscientific diets tell you you must have, or the advice to snack constantly I get from brochures at my local YMCA. Hunter-gatherers tend to eat a few leftovers in the morning, hunt all day and then have a big meal at the end of the day - sounds pretty similar. I doubt if in paleolithic times they very often fasted on purpose, but I do believe they were adapted to food scarcity.

Reader Comments (18)

I've been doing the same thing now for over a year. Never eat 3 meals. One or 2 is just fine. I regularly do 1 or 2 24hr fasts a week. It's not that hard really. In the process I've lost 25 lbs without counting calories. I've also cut the cord on sugary junk. For those who claim women have a harder time with this - that's total BS. A 125 lb. woman just doesn't need that many calories even if she's active. It makes me angry to see all the stupid dietary advice the so called nutritional experts put out there on the air waves. No wonder people can't lose weight. When people ask me how I've lost so much weight and I tell them intermittent fasting, they are stunned. Also, I train with kettlebells and heavy weights almost always in a fasted state. No problem. I hope blogs like this and EatStiopEat can get the word out to people that eating all the time is just not necessary or good for you .

June 24, 2009 | Unregistered CommenterDenise DeGrazia

I've been practicing intermittent fasting now for over a year and I'm really sorry I didn't find out about it sooner since it has changed my life. I've lost 25 lbs without counting calories or stressing about what to eat. I've cut the cord on sugar and find that my food tastes have changed quite a bit. I do one or two 24hr fasts a week and never eat anything before noon.
It's not hard at all and it gets easier with time. I regularly train with kettlebells and heavy weights fasted. I have no problems with this.
It really makes me angry to see the kind of BS that passes as dietary advice on the airwaves by so-called dietary experts. No wonder people are fat and can't lose weight. I hope that the word on IF gets out to a wider audience. Good luck with this blog. I've bookmarked it as it has a lot of useful stuff.

June 24, 2009 | Unregistered CommenterDenise DeGrazia

Sorry about the double posts. I wasn't able to see the first post and thought it didn't go through. You can delete the duplicate if you like.

June 24, 2009 | Unregistered CommenterDenise DeGrazia

I'm curious about the size of the meals you eat. I am one of those people who has followed the "you've got to eat breakfast" advice, but my natural tendency would be to eat later in the morning, like 11. But by then I would also be quite hungry and would want a big meal. Same for evening food. Are you eating 2 large meals?

June 25, 2009 | Unregistered CommenterJohn

Denise -

Glad to hear of your success. Being stubborn, arrogant and skeptical, I ate eggs, bacon and plenty of meat despite being harassed throughout my career for it. When I heard Taubes on NPR saying the pasta I never really favored without meat sauce on it was the stuff killing me, and that fiber was a lie, I too was angry. I am now trying to fight back.

Thanks for your support


Hey John

One of my dogmas is that paleolithic creatures like big cats, small mammals and, say naked hominids must have somehow evolved mechanisms to regulate portion size without scales, calculators or bomb calorimeters. Part of this is just temperamental with me. I took math through differential equations in college, but I abhor the idea that weighing and measuring and supplements is the key to health the way I abhor the idea of saying a special prayer might get you in to heaven. I think books that tell you you need to measure and weigh your food and memorize what they contain are a bit ridiculous and contribute to the medicalization of diet.

Sorry for the rant. I am saying I don't know if my meals are "big" or not. I eat twice a day and I stop eating when satiated. I suspect my caloric intake is lower than when I was about 45% carbs and a wheat-eater and that there is also a modest metabolic advantage as well.

I think the key is getting close enough to ketosis that the fasting happens spontaneously.


June 25, 2009 | Registered CommenterKurt G. Harris MD

Great site, really appreciate the great info. One question: Do you recommend a set number of protein grams per day? I'm getting about 170 to 180 grams per day, about 1 per lb of body weight.
Doing Crossfit workouts about 5 times a week.

July 6, 2009 | Unregistered CommenterJustin

Hello Justin

That is certainly more than enough protein. Protein has insulin effects but if you are otherwise free of insulin resistance issues and are gluten free and low carb, I don't think getting excess protein from healthy sources is an issue.

My approach is to follow the rules without counting or measuring, then once in a while put a day or two's intake into fitday - if you are below 15% protein and trying to be competitive, then you might add some, if you are in the 15-25% range I think that is fine. If you chase animal fats from a variety of good sources and keep carbs around 10%, you will probably be in the 20-25% range unless you only eat butter and cream for your fats.

Avoiding grains and starches, seeking fats from animal sources and using common sense will usually get you good ratios - the fitday exercise is just to "check your work" .

July 6, 2009 | Registered CommenterKurt G. Harris MD

Reading more of your posts I see that I should give up the olive oil and cook with butter.
As of right now my Fitday percentages are P-44, F-41, C-10. Have no idea where the other 5% went, ha.
Going with right around 45-50 grams of carbs a day and love how my body comp is changing.
Keep up the great posts, thanks.


July 6, 2009 | Unregistered CommenterJustin

"I began to fast spontaneously a few months into eating low carb (my percentages are about 65% fat, 25% protein and 10% carbs). On LC, the character of hunger changes completely. Without swings in blood glucose, and with cellular adaptation towards fatty acid metabolism, the "sick' sort of hunger that most people think of as hunger goes away. I find that I can arbitrarily fast for up to 18 hours with no discomfort whatsoever."

Although my percentages may possibly differ slightly to yours (I broadly halve my plate and fill one half with a BIG piece of choice meat including any fat that comes with the cut, and the other half with seasonal vegetables/salad), my experience is pretty much the same as yours.

I began paleo/low carbing nearly three years ago. After a few months I trusted my hunger/appetite and started to skip breakfast. This then progressed on to eating once or twice a day with no need for snacking. I eat around lunchtime and again in the evening (often quite late).

I was slightly worried at first that although instinctive, this behaviour had possibly adverse effects. It is somewhat encouraging reading your post - especially the bit 'I eat around noon and again about 9 pm most days'. I often consoled myself with the idea that if you can't trust your hunger - then what the hell is it for? I mean we trust fatigue to tell us when to rest, and thirst to let us know when to drink!

Love your site and it is great that another member of the medical community, having 'gone paleo', is willing to not only follow the evidence but to also offer support to the wider paleo community.

July 16, 2009 | Unregistered CommenterAsclepius

Hi Kurt,

I finally saw the light just over 12 months ago when after many years of counting calories and sticking rigidly to diets, I just couldnt lose even a pound. My weight just went up and down each week. Tried Atkins about 2 years ago, found I finally started to lose weight. The read Gary Taubes.......wow. What an eye opener for me....then suddenly everything made sense. I found Peter's site Hyperlipid and there's been no going back. I've lost 45 pounds in 12 months! Feel fantastic, no more low grade depression, no more rhinitus, no more asthma attacks (been medication free for 10 months) no more eczema.
I take scrambled egg in butter to work each day and eat it about 11 -12
I drink coffee with 40% fat content cream
Then meat of some sort or another preferably fatty (pork is good) for my evening meal between 7 and 9.
Add in a bit of dark chocolate when I feel like it and thats virtually it for me
I dont get much daylight Monday to Friday, so I supplement with 6000 Vit D per day and also 2grams VitC
My family, friends and work colleagues think I'm the strangest thing ever, and all tell me I'll die of heart disease very soon.
I'm a 50 year old female and have never felt better in my life.


August 15, 2009 | Unregistered Commenterdizzywiz

What would you suggest for those with hypoglycemia in a moderate/chronic form. I tend to collapse and faint shortly after waking up as a result of "fasting" for 6 hours thruout the night and the standard treatment is to have soda(or other heavily sugared) water near my side so I can drink it upon waking up, which does help, but I am working on getting rid of sugar from my diet. A fair number of people do have this condition, as do many type one diabetics, and the sugar "crash" that follows isn't good at all. Would fruit have enough quickly digestible sugar to help with this(My regular doctor suggests only sugar water, since the fiber in fruits inhibits breakdown, but they are also traditional doctors who do not support the Paleolithic diet)? I currently get about 60% of my calories from fat(eggs, dairy and cold pressed flax/olive oil/coconut oil, which I understand are some of the "healthier" vegetable oils(With coconut added for the extra saturated fats that I do not get from meat).), 30% from carbs(Mostly fruit at this point) and 10% from protein(I am working on increasing the protein, though I do get the "required" 40 grams a day) on a vegetarian diet(heavy on eggs. Lack of "clean" meat(Humanely treated, grass fed, organic ish, hormone free(Grocer only stocks nonorganic grain fed beef, and I have yet to find a local farmer who slaughters animals and grass feeds them, and venison is very hard to find out of season.)) bothers me and quite frankly, the conditions in the average slaughter house(Based on a tour of one near relatives) disturb me enough to want to avoid it, and I have finally found a clean egg producer that has "pastured" eggs, hence why I now eat those, and my dairy is goat/sheep from a family farm.). Should a person with my condition simply have sugar only as part of that morning routine? Should they avoid fasting all together? Basically, is there any safe way for a person with hypogycemia to fast? Or is there not enough benefit to fasting so that it is a good idea to avoid it if you have a medical condition that discourages fasting?

August 28, 2009 | Unregistered CommenterAnn

"I eat around noon and again about 9 pm most days. So every 24 hours has a 15 hour fast and once in a while up to 18 hours."

I started zc 19 days ago and have fallen naturally into this pattern, too, without intending to, although my hours are two or three earlier than yours because I go to bed earlier. So I eat between 9 and 11am and again between 4 and 7pm, so every 24 hours also has a 15-hour fast and like you sometimes up to 18hrs.

September 7, 2009 | Unregistered CommenterHelena

Wow, so I've been trying this out for 2 days now, and today I decided to lift during my fast. It was incredible I did so much better than on days when I've eaten before and, even when I've eaten a good amount of carbs, I super excited now to continue this way! I lift pretty heavy and do mma quite a bit during the week, my goal is fat loss though, so Im doing just potatoes after my workout, wondering does it matter how soon you need to eat after a heavy weight training session, would love to see more blogs on IFing!! and as it pertains to lifting etc. Also Martin B. of LeanGains, I like some of his work except for his low fat approach... Thanks for the great blogs! -Amanda

September 13, 2009 | Unregistered CommenterAmanda T.

I want to chime in - I'm a female in my late 20s, and I've never been a breakfast eater. Sure, I've eaten breakfast, but it never came naturally to me, and I've always found typical breakfasts nauseating.
Since my early teenage years, I've varied between no breakfast, a little fruit only for breakfast (1 grapefruit), big fruit smoothies with coconut cream, bran cereal with water, or steamed green vegetables. Eating anything substantial early in the morning totally grosses me out. I am generally fine with NO breakfast, just water and maybe a little unsweet hot tea. Then I'll feel gradually hungry for lunch. 2nd best is a little fruit, or the steamed veggies, but this leaves me ravenously hungry by lunchtime. If I were to eat a giant breakfast (eggs, bacon, sausage, pancakes, waffles, OJ, etc...) I would feel so sick!
And on Saturdays I've always fasted until a lunch in the middle of the afternoon.
No breakfast just comes naturally to me. Glad I never did listen to the naggers blabbing about how "breakfast is the most important meal of the day" while sanctimoniously eating their PopTarts and juice...

September 29, 2009 | Unregistered CommenterBubbles

Just wondering about exercising in a fasting state - do you recommend eating my first meal after my morning workout? I just began IF a couple of days ago and am feeling a bit mushy...I'm in my late 20s, about 115 lbs. and kettlebell/strength train 6 days/week. I have not had much success dropping those last few fat pounds via the Zone, so I figured I would try this. Yesterday I was very tired and lethargic all afternoon so I bumped my carb intake up today and felt more 'with it'...just wondering if it takes an adjustment period, and if so...about how long?

October 12, 2009 | Unregistered CommenterJessica

Do you have any evidence to back up your assertion that hunter-gatherers eat some left-overs in the morning, spend all day hunting and feast at night??? Isn't that sort of counter-intuitive in that they are hunter GATHERERS and would be nibbling on whatever they found that was edible while out searching for game? And do you have any evidence that supports that hunter gatherers actually act lots of meat every day?

October 14, 2009 | Unregistered Commenternxm



Try readiing "Catching FIre" by Richard Wrangham and "Meat eating and human evolution" by Stanford and Bunn also "Evolution of the human diet" an academic symposium edited by Peter Ungar.

Hundreds of references therein.


The zone is pseudoscientific bunk. It only "works" by accident because you are reducing carbs from 50 to 30%. Sears macronutrient ratios theory is groundless, frankly. Avoidance of wheat and linoleic acid is not even addressed by Sears.

There is definitely an adjustment period - weeks at least. I would eat about an hour or two after your AM workout, but once keotadapted, you could wait longer if you wanted to.

October 15, 2009 | Unregistered CommenterKurt G. Harris MD

i am trying to find out about potassium needs. recently i discovered that the requirement for potassium is much higher than the 99 mg rda. how can the paleo diet provide several grams of k / day ? how did paleo man eat mountains of fruits and vegetables?

October 19, 2009 | Unregistered Commenters letteer
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