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. counting calories and following the usda food pyramid is HOPELESS. It’s too bad so many people have been nothing short of brainwashed and don’t realize there is a better way!

    Fixed Gear wrote on May 27th, 2009
  2. Fixed Gear~
    I think that alot of that will come to change in future generations. I find the whole “Well if the doctor says I should tie these cinder blocks to my feet and jump into a canal, I guess its what’s best for my health.” mentality more common among my parents/similarly aged people. Unfortunately with the recent economic collapse I am sure there are people forgetting everything about anything diet related and are sticking with the bare minimum “I need to put food in my/my kid’s mouth.” and what is most easily availiable is highly processed grain.

    Love the article, It backs my general thoughts on eating with empirical data, the most important of which is that fat dosen’t go sideways out of your stomach and into your belly. I’ve always believed that when you digest food you turn it into other things (hence we dont flush pork chops and beer) so you would be pretty hard pressed to get fat from fat, since it will turn into something *not* fat.

    I was wondering if you could help me try to *gain* weight. I seem to have hit a wall at 140. I’m lean so I did my fat% at 16%. Im an intense exerciser so I do 1g/lb protien which is ~120g with about 95g carbs and 80g fat. Not sure if I need to up the protien or maybe the carbs (I run 6x a week mon/wed/fri 1 mile sprint slow to jog if I can’t make the full dist. usually get 3/4, tue/thur 3 mile interval, sat 5 mile brisk jog along with the anaerobics I do to gain muscle mass) so maybe I need more carbs to keep the running from eating my muscles for energy?

    Only thing with that is like you say in your article its way hard to get many more carbs without picking up some wonderbread…

    Gearford wrote on July 22nd, 2009
  3. im not sure how the whole insulin hormone whatever thing works. i just eat wen im hungry. i have fruits, tree nuts, veggies and meat, and the occasional baked sweet potato. i eat generally watever is in season, and i buy most of my weekly requirements from the farmers markets on saturdays and thursdays.

    shastagirl wrote on July 24th, 2009
  4. I’ve been doing lower carb for years, but having Type 1 Diabetes, the insulin I have to take, puts on weight… 14kg since 2006, and 4kg since June when I went on an insulin pump. However, my blood glucose levels have drastically improved. I need to lose about 20kg. The dietician said I wasn’t eating enough carbs so I’m not losing weight. Wrong! I also rarely eat fruit.

    Great discussion about fructose here: and it emphasizes the importance of fibre and exercise and talks about fructose metabolism.

    As a result of the way I eat (under 120 carbs a day, but do better under 80), I’m on much less insulin than most for my weight. I do have one weakness – good quality dark chocolate. Still grappling with that one, and I certainly don’t have it every day. But… my issue is that I have other autoimmune diseases (arthritic) as well, and exercise is a form of torture. Somehow it must be added, and not for burning calories. I try, then I’m down for days. No swimming pool anywhere close. Pity. Any suggestions of what I can do for very low impact exercise? Walking is out – too painful (needing a knee replacement, and have arthritis in my spine). Would Yoga be good?

    I’m also one of those with super-high cholesterol – have had as long as it’s been measured. I refuse to take statins. Fish oil isn’t making much difference. Not sure what will – even a vegan diet years ago didn’t make much difference.

    My liver seems to really good at dumping glucose when it’s not required, which of course, raises my insulin needs. So really my overzealous liver is likely the problem.

    Would really appreciate some advice.

    sooz wrote on August 29th, 2009
    • Dark chocolate is my crutch also. Good luck and don’t give up!

      MR! Stoner2udude wrote on September 27th, 2011
  5. Hey Mark,

    I have a question about lowish carbs and sleep. I noticed you mentioned that 80g is still on the high end and that if you lower them between 20-50 you’ll lose fat quicker..well I know this personally to be true! The thing I find when I cut my carbs is that I cannot sleep at night for the life of me. Even at around 50-100 my sleep isn’t as great as if I were eating more. Yet, the more carbs I eat the harder it is for me to lose fat, the lower my calories must be, and the IBS symptoms become unbearable. Lowish carb makes my tummy happy.
    Do you know any correlation between carbs and sleep?

    Heather wrote on December 16th, 2009
  6. Oops let me re-phrase my question above so I don’t sound like an idiot. I know there is a strong correlation between carbs and sleep. I’ve researched this like crazy. BUT, how can you manage it and still eat low carb? I’ve heard of taking melatonin but this does not work for me.
    Thanks again!

    Heather wrote on December 16th, 2009
    • Heather, the correlation between sleep and carbs is, in my estimation, a loose one based on carbs’ relationship to serotonin. After a time on a low carb plan, theoretically, your sleep adjusts. There may be other factors involved, though, like stress, ambient light, time-of-life hormone balance, etc. I say that if you are allowing yourself enough time for sleep, your body should do fine. There’s no law that says we have to sleep straight through the night, either. Some people lose sleep worrying over how much sleep they are losing!! Finally, I’m not a huge fan of taking melatonin regularly (I do, however, use it to reset my internal clock when I cross more than three time zones traveling).

      Mark Sisson wrote on December 16th, 2009
  7. Awesome article. I too have encountered the ridiculousness of a registered dietician. He was on about 65% of the diet being comprised of carbs. I wanted to stab my eyes out.

    FitJerks Fitness Blog wrote on January 4th, 2010
  8. Hi Mark and all other posters!.Im struggling to understand the amount of carbs per day…it says 100g-150g/per day, but I had a small salad (lettuce/spinach, cherry toms, shredded carrot) and it came to nearly 100g, just in 1 small salad! I am misunderstanding something?? Any help would be much appreciated

    Phil wrote on January 20th, 2010
  9. Hello just wondering Im into bodybuilding age 28, workout 5 days a week and currently have a lean and muscular body already at about 8% bodyfat. Im interested in following this diet but afraid would this slow my gains?
    As some that I read that you need to have carbs after workout and carbs to grow would 50-150gm be enough? I’ve always been sticking to low GI carbs Quick Oats mainly.

    BodybuildingJunkie wrote on January 27th, 2010
  10. Heather,
    I wanted to respond to you because I have the exact same issue. No matter how good it is for you, dropping carbs too quickly can really mess with your blood sugar. Some people can tolerate it better than others. It’s just like quitting caffeine; some people can go cold turkey and suffer only minor withdrawal symptoms but others really struggle and have to wean themselves off slowly.

    What’s likely keeping you up/waking you up is hypoglycemia/hyperinsulemia. I suffered from chronic insomnia for 4 months before I finally figured it out. Your blood sugar dips too low and your body has what’s called a “vigilant response”; it releases adrenaline to up your glucose levels so your basic bodily functions can still occur. That’s what wakes you up. To get back on track, I’ve upped my carbs so I can sleep, then I’m going to slowly start cutting back so as not to shock my system again. I’ve also started taking a cinnamon supplement, and I’ve noticed that within minutes of taking it my hunger pains have subsided and my blood sugar evens out.

    Sleep is too important for anyone to dismiss. It has been tied to obesity, difficulty regulating blood sugar, and a deficient immune system, just to name a few. It impairs your reaction times the same way being drunk does. It is also the single most important thing you can do to repair your adrenals if they’re fatigued. When you don’t sleep, your body has to pump out all sorts of stuff (cortisol, adrenaline) that are horrible for your body over a prolonged period of time. Too much cortisol in particular raises blood sugar and insulin levels and makes it very difficult to lose weight. Did you know that most of your fat burning occurs when you sleep? So if you’re not sleeping, you’re not burning fat. You’re also not releasing human growth hormone the way you need to, which has tremendous fat burning and anti-aging effects.

    I hope this helps. I know how frustrating and stressful insomnia is, and most of us do not have the luxury of shrugging it off. Good luck to you.

    klamolsch wrote on February 8th, 2010

Leave a Reply

If you'd like to add an avatar to all of your comments click here!

© 2016 Mark's Daily Apple

Subscribe to the Newsletter and Get a Free Copy
of Mark Sisson's Fitness eBook and more!