Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
30 Jul

The Definitive Guide to the Primal Eating Plan

Food Scale

Do the Math

In my recent Context of Calories post, I explained how the different macronutrients we eat at each meal (fats, proteins, and carbohydrates) have different effects in the body. I suggested that, despite their raw calorie values, it’s far more important to get a lasting intuitive sense of how much of each macronutrient you need and when you need it (or not).

But how do you do that? How do you figure out the proper number of calories – and breakdown of fats, protein and carbs – to accomplish your fitness and health goals? To lose weight? Lose fat? Gain muscle? Maintain status quo? Run marathons?

In fact, most popular daily diets look at overall calories as the main factor in weight loss and weight gain. The age-old conservation of energy Conventional Wisdom says that “a calorie is a calorie.” From there most diet gurus generally prescribe some formulaic one-size-fits-all breakdown of fats, protein and carbs. A classically trained Registered Dietician will tell you that protein should be around 10-15% of calories, carbs should be 60% (and mostly from whole grains) and fat under 30%. This macronutrient breakdown stays the same regardless of how much weight you need to lose or what other goals you might have. Barry Sears has his 40/30/30 “Zone” diet. The USDA bases everything on a choice of between 2,000 and 2,500 calories a day. But, as I said earlier, it’s not that simple. Calories do have context.

The human body uses these macronutrients for a variety of different functions, some of which are structural and some of which are simply to provide energy – immediately or well into the future. Moreover, with regards to energy conservation or expenditure, the body acts as both an efficient fuel storage depot (and as a toxic “waist” site) as well as a potent generator of energy, depending largely on the hormonal signals it gets. It will store glycogen and/or fat and it will build muscle – or it will just as easily tear them all down and use them for fuel – based on input from you: what you eat, how much you eat, when you eat, what you’re doing before or after you eat – even what you’re thinking when you eat. Yet because your body always seeks to achieve homeostasis over time, the notion of you trying to zero in on a precise day-to-day or meal-to-meal eating plan is generally fruitless (yes, Charlotte, some fruit is allowed). The good news in all this is that falling off the wagon once or twice this week won’t have the immediate disastrous effect that you might imagine – as long as you can keep your average intake under control and understand how the various macronutrients function over time.

Which brings me to the crux of today’s discussion. Not only is it nearly impossible to accurately gauge your exact meal-to-meal calorie and macronutrient requirements, doing so will drive you crazy. In fact, to accurately figure your true structural and functional fuel needs (and hence to achieve your goals) it’s far more effective to look at a much larger span of time, like a few weeks, and aim for an “average” consumption. Then you can review that average daily intake over weeks or months and adjust accordingly. Below, I’ll give you a way to figure a “jumping off” point to start with, but remember, our genes are accustomed to the way our ancestors ate: intermittently, sporadically, sometimes in large quantities, and sometimes not at all for days. Their bodies figured out a way to maintain homeostasis and preserve lean tissue and good health through all this and so can we. Our genes want us to be lean and fit. It’s actually quite easy as long as we eat from the long list of Primal Blueprint healthy foods and try to avoid that other list of grain-laden, sugary, processed and otherwise unhealthy foods. Realistically, we also want to allow for the occasional party-splurge, a pre-planned (or accidental) intermittent fast, an over-the-top workout or even a week of laziness. Where most people get into trouble is in miscalculating their energy needs over extended periods of time – not day-to-day. They don’t see the average amount of carbs creeping upwards, or they figure they need x amount of calories, but don’t have a clue as to what kind of food those should be coming from.

I start with these four basic principles to guide my Primal Blueprint eating style:

1) 80% of your body composition will be determined by your diet. Yes, exercise is also important to health and to speed up fat-burning and muscle-building, but most of your results will come from how you eat. I’ll write more on this later, so just trust me on this one for now. Suffice to say, people who weigh a ton and exercise a ton, but eat a ton, still tend to weigh a ton. I think I’ll have that made into a t-shirt…

2) Lean Body Mass (LBM) is the key to life. I’ve said it many times on this site: lean mass (muscle and all the rest of you that is not fat) is directly correlated with longevity and excellent health. Rather than strive to “lose weight”, most people would be better off striving to lose only fat and to build or maintain muscle. Since other organs tend to function at a level that correlates to muscle mass, the more muscle you maintain throughout life, the more “organ reserve” you’ll have (i.e. the better the rest of you will work). Refer back to rule #1 and eat to build or maintain muscle.

3) Excess body fat is bad. Most human studies show that being significantly overweight increases your risk of nearly every disease (except osteoporosis – because ironically it responds to weight-bearing activities). Fat just doesn’t look that great either. See rule #1 and eat to keep body fat relatively low.

4) Excess insulin is bad. We’ve written about it here a lot. Chronic excess insulin may be even worse than excess sugar (and we know how bad that is). All animals produce insulin, but within any species, those that produce less insulin live longer than those who produce a lot. Eat to keep insulin low.

Here is how I use these principles to guide my individual macronutrient intake:


Raw Steak

Protein takes priority. If there is ample glycogen (stored glucose) and the body is getting the rest of its energy efficiently from fats, protein will always go first towards repair or building cells or enzymes. In that context, it hardly seems fair to assign it a “burn rate” of 4 calories per gram. It’s like saying the 2×4 studs that support the walls of your house can burn nicely if you run out of firewood. They will, but I prefer to burn other fuel first. At a minimum you need .5 grams of protein per pound of lean mass/per day on average to maintain your “structure”. If you are moderately active you need .7 or .8, and if you are an active athlete you need as much as 1 gram of protein per pound of lean mass. That’s at a minimum, but it’s on a daily average. So a 155 lb moderately active woman who has 25% body fat (and thus) has 116 lb of lean body mass needs 93 grams of protein on average per day (116 x .8). If she gets 60 or 80 some days and 110 on others, she’ll still be in a healthy average range. And even if she exceeds the 110, it’s no problem if she’s eating low carb because the excess protein will convert to glucose, which will reduce her effective carbohydrate needs (see below). At 4 calories per gram, that’s between 320 and 440 calories per day in protein. It’s not that much.



If you’ve forgotten everything you ever learned in biology, just remember this and “own” it: Carbohydrate drives insulin drives fat (Cahill 1965, and Taubes 2007). The idea in the PB is to limit your carbs to only those you need to provide glucose for the brain and for some reasonable amount (certainly less than an hour) of occasional anaerobic exercise. And the truth is, you don’t even need glucose to fuel the brain. Ketones from a very-low carb diet work extremely efficiently at that task. Either way, ideally, we would like most of our daily energy to come from dietary or stored fats. Typically, (if you are at an ideal body composition now) I use a rule of thumb that 100-150 grams of carbohydrate per day is plenty to keep you out of ketosis (and ketosis is NOT a bad thing) but away from storing the excess as fat if you are the least bit active. Don’t forget that your body can make up to 200 grams of glycogen from fats and protein every day, too. On the other hand, if you are looking to lose body fat, keeping carbs to under 80 grams per day will help immensely in lowering insulin and taking fat out of storage. On the other other hand, if you are insistent on training hard for long periods of time, you would add more carbs (say, 100 per day extra for every extra hour you train hard). It becomes a matter of doing the math and experimenting with the results.

Ironically, it’s tough to exceed 100 grams of carbs even if you eat tons of colorful vegetables – as long as you eat like our ancestors and consume no grains, no sugars and few starchy vegetables (potatoes, yams, beets, legumes, etc). Even if you eat a ton of vegetables AND a fair amount of fruit, you’ll be hard pressed to exceed 150 grams of carbs on average per day. Our remote ancestors couldn’t average 150 grams of carbs a day if they tried, yet they had plenty of energy and maintained their lean mass. At 4 calories per gram that’s only between 400 and 600 calories per day. Add that in to the protein above and our sample girl is barely at 1,000 calories on the high end. So where does the rest of the fuel come from?


Olive Oil

Learn to love them. They are the fuel of choice and should become the balance of your Primal Blueprint diet. Fats have little or no impact on insulin and, as a result, promote the burning of both dietary and stored (adipose) fat as fuel. Think about this: if protein and carbs stay fairly constant (and carbs stay under 150), you can use fat as the major energy variable in your diet. Feeling like you need more fuel (and you’ve already covered your bases with protein and carbs)? Reach for something with fat. Nuts, avocados, coconut, eggs, butter, olive oil, fish, chicken, lamb, beef, the list is a long one. 100 grams of fats per day would only add 900 calories to our girl’s daily average, putting her at between 1620 and 1940 calories a day. Even if she averages somewhere between 1400 and 2200 calories per day over a few weeks, as long as she pays attention to protein and carbs, her body composition will shift to lower body fat and more desirable lean mass. If she decides to do some walking, a few brief intense weight sessions and a sprint day here and there, that process would accelerate greatly. If she gets to a point where she’s content with her body fat, she can even add in a little more fat to provide energy that she previously got from her stored fat.

The main thing I’ve figured out from eating this way for years is that I don’t need nearly as many calories to maintain health, mass, and body fat as I once thought I did – or as the Conventional Wisdom says I do. I eat 600-1000 calories per day less than when I ate a carbohydrate-based diet, yet I maintain slightly lower body fat and slightly higher muscle mass on even less training. Remember: 80% of body composition is determined by diet. The best part is that I don’t ever feel hungry because I base my eating on exactly what my 10,000-year-old genes want me to eat.

For a look at my upcoming book, The Primal Blueprint, click here. I’ve included a sneak peek at the jacket artwork, a PDF of the table of contents and full chapter summaries.

Further Reading:

Definitive Guides to:

The Primal Blueprint




Insulin, Blood Sugar and Type 2 Diabetes

Stress, Cortisol and the Adrenals

Prefer listening to reading? Get an audio recording of this blog post, and subscribe to the Primal Blueprint Podcast on iTunes for instant access to all past, present and future episodes here.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I do like a lot of what you say and the premises of the diet. But, what I have learned and read suggests that we are closer to about 5000 years behind our “culture evolution”, not 10,000. Is there a reason you are attempting to base it closely on 10,000 years ago? I often think that the 5000 years makes a lot of sense, especially when we consider that more and more people seem to be becoming tolerant of grains (I do realize that most people believe they are tolerant and are probably not, but it seems that some people truly are). I am curious about your ideas on this. Oh, and I am NOT one of those grain tolerant ones… LOL

    Shantelle wrote on February 10th, 2011
  2. More tolerant of grains? There are things happening on a cellular level when we eat grains (not to mention insulin response)that we don’t even know about and people with aches, pains, heeadaches, hormone imbalance mood swings…probably from the processed foods they are eating. Thems GRAINS.

    DBeee! wrote on February 10th, 2011
  3. JUST found you, and glad I have~! I’m wondering, Mark… what about dairy? Goat cheese? Almond milk unsweetened? eggs? Thanks!

    Dianna wrote on February 11th, 2011
  4. also…….. meant to ask, what if I do not live near a beach? what kind of surface do you recommend for the sprint?

    Dianna wrote on February 11th, 2011
  5. So how would i go about figuring out the amount of carbs that i am eating through out the day?

    Chanel wrote on March 9th, 2011
  6. Hi Mark…

    I’ve searched all over to find some good advice on my particular situation because it’s so extreme. Here goes…
    I’m 73 years old, 5’8″ and weigh around 350 lbs. I need a rollator to get around and because of congestive heart failure I get winded with not much exertion. I move around my apartment, and except for taking the elevator downstairs to check my mail a few times a week and going to the laundry room, that’s pretty much it. I have no idea how many calories I burn a day but it can’t be much. Is there anything that you know of that might be helpful for someone like me? I really don’t want to be buried in a piano case if I can help it!


    Jim Flanagan wrote on March 10th, 2011
  7. I’m pretty convinced but I do have a question that is keeping me in confusion about these carbs. If say I want to aim for 150 grams of carbs a day cause I know i’m active, is fiber also accountable? Whenever I input fiber out of the total carbs i’ve eaten it subtracts. I’m guessing cause your body burns calories just passing fiber? I honestly dont know why but what role does fiber play with carb intake? If i eat say 95 grams protein, 100 grams fat and 150 grams carbs and 15 grams of it is fiber does it add up to 1820 calories or 1880? i’ve been using this site to check my macronutrients

    steff wrote on April 29th, 2011
  8. I am finding this conversation fascinating, and inspiring, but I have some trouble buying the premise that our primal ancestors were healthy. They were lean, most likely, but healthy? ON what do you base that assumption? My understanding is that people lived to be about 35, if they were lucky, in the times when the most available source of food was meat. I’m aware of the plethora of diet-related diseases today, but I am curious how you came to the conclusion that “early man” was somehow much healthier than we – as a population – are today.

    Cassandra wrote on May 23rd, 2011
    • The 35 year average thing is really misunderstood. People weren’t simply dropping dead at age 35 from bad health or some bizarre early onset of old age. The 35 year mark is an average lifespan of a population. And it’s heavily skewed downward by things like infant mortality, mothers’ deaths in childbirth, and a hostile environment full of dangerous animals and other natural perils. Those people that survived to adulthood and avoided being eaten or otherwise killed tended to be quite robust (they had to be, in general, otherwise life selected them for removal) and lived within the normal age range of human beings. Our dramatic increase in the average age we have today is due to scientific breakthroughs in sterilization and infection prevention, vast improvements in the infant mortality rate, and far fewer people being eaten by lions and killed by exposure to the elements.

      JTW wrote on July 22nd, 2011
  9. Mark,

    This was very helpful; especially the sample girl you referenced. Those stats are similar to mine. I weigh 155lbs, body fat 24% and LBM is about the same. I’ve been struggling with my paleo mainly because the lingo/terms I’m not always familiar with, so many times I just don’t understand what everything really means. This article was very helpful, but now I’m wondering if I’m eating to much protein. According to your sample I should be around 4ounces a day, but I’m definitely eating WAY more. What is too much? Thank you Mark – I greatly appreciate you!

    Elena wrote on July 13th, 2011
    • This reply is so late you will probably never see it, but 4 oz of meat is not 4 oz of protein. More like 25 grams of protein, or less than 1 oz. Read nutrition labels.

      Roy wrote on January 28th, 2014
  10. Mark, do you have an easy way of figuring grams!? I am totally confused about how to figure it.

    Dianna wrote on July 14th, 2011
  11. Mark,

    You express that ketones work efficiently to fuel your brain. While I agree with that in terms of a person in starvation mode who needs to utilize all they can in order to avoid death, how do you address the risk of ketoacidosis? I was also wondering what specific formal medical or nutrition training you’ve had?

    J wrote on July 26th, 2011
  12. Interesting information. I was wondering – you mention things like butter and olive oil. What’s your take on fats like lard or beef tallow?

    Oliver wrote on August 6th, 2011

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