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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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May 29 2019

The Keto Carb Threshold: What Constitutes a “Keto” Meal?

By Mark Sisson
20 Comments

How many carbs can you eat in a sitting and still “stay keto”? What constitutes a “keto meal”?

I’ve gotten many questions about this topic.

First of all, let’s get this out of the way: Keto is not a religion that punishes heretics with eternal damnation (or eternal reliance on exogenous sugar for energy). This post is not intended to make people feel guilty for eating five grams of carbs over the” limit.” It’s not even intended to set a hard limit in stone. It’s simply to provide people who care about this sort of thing a basic, admittedly rough, guideline for staying below the keto carb threshold within meals throughout the day.

First of all… there’s a problem with establishing a universal keto carb threshold….

Why Universal Keto Carb Thresholds are Problematic

Carb thresholds are a very personal thing. Not in the sense that you should only tally up your within-meal carb counts behind closed (and locked) doors, but in the sense that they are extremely context dependent:

  • The number of carbs that knock a person out of ketosis will differ from the amount that will knock another person out of ketosis for genetic reasons.
  • The number of carbs that knock a person out of ketosis will differ day to day and meal to meal based on his or her exercise and activity levels.
  • The number of carbs that knock a person out of ketosis will differ based on ketone- and fat-adaptation status.
  • The number of carbs you’ve eaten in previous meals and the amount of carbs you plan on eating in subsequent ones influence how much you should eat at this meal.

We All Have Different Genetic Keto Thresholds

Take the Inuit, for example. Despite eating almost nothing but seafood and marine and land mammals and their fat, with negligible amounts of carbohydrates, the Inuit rarely show evidence of ketosis. A legitimate fast isn’t even enough to reliably produce ketosis in the Inuit. It turns out that many of them possess a gene variant that prevents ketosis and drops blood sugar during fasting and starvation. They’re great at burning fat directly, not so good at reaching ketosis. Even if we’re not talking about Inuits, every single person has different genetic potentials for generating ketones and responding to carbs.

How You Exercise Has a Huge Effect

If you create a glycogen debt through intense training, a significant portion of the carbs you eat immediately after will go toward replenishing that glycogen rather than contribute toward your energy consumption. You can remain in ketosis and store those carbs away in your muscle. Exercise alone stimulates ketosis independent of diet; if you’re a highly active person, you’re probably already dipping in and out of ketosis without even changing what you eat. Your carb threshold will be higher.

How Far Along You Are In Your Keto Adaptation Has An Effect

At this point, I can have a big sweet potato with dinner and be right back to ketosis in the morning. I can eat beef larb salad over some steamed jasmine rice for lunch and coconut curry for dinner while on vacation in Thailand and bounce right back without issue. Because I’m fully ketone-adapted and fat-adapted, and my mitochondria are adept at burning fat, I have the metabolic flexibility to drift in and and out of ketosis as I please. The idea of a hard “keto threshold” becomes less relevant when you’re fully keto-adapted.

How Many Carbs You’ve Already Eaten (and Will Eat) Also Figure In

If you’ve already eaten 40 grams of carbs for breakfast, you have very little leeway for future meals. If you had bacon, eggs, and steak for breakfast, you can handle a larger dose of carbs.

Making things even harder, these contexts are impossible for the average person to quantify. It’s hard to tell exactly how much glycogen debt we’ve incurred through our training—how many carbs we’ve cleared out and can safely assimilate. It’s impossible to quantify our genetic keto threshold, and you can’t exactly count the fat-burning mitochondria you’ve generated or put a number to your degree of ketone-adaptation.

Why Keto Carb Thresholds Are Helpful

Everything is fuzzy at the margins. Very little in life and the universe is totally binary and clear-cut. But thinking of the world in binary terms and separating things into categories can be helpful. Too much fuzzy thinking renders making decisions hard. It breeds indecision. It paralyzes. We need something.

That’s where a keto carb threshold for determining “keto meals” comes in: Despite the very real limitations of establishing a true keto threshold, they can be helpful for beginners and other people trying to make decisions about what to eat.

Imagine you’re a beginner to this Keto Reset thing. Do you want to have to consider how many carbs you’ve burned through exercise today, which genes you have, or whether you’ve successfully produced enough fat-adapted mitochondria before deciding on how many carbs you can get away with? Or do you want a number that may be imperfect but will probably get you in the ballpark?

“Eat this many.”

“Stay under this number.”

“Avoid this.”

“Eat that.”

Simple things you can have as touchstones and landmarks when you’re getting started and progressing along your journey…

Keto Carb Thresholds: So, How Much Per Meal?

All that said, here are some good rules of thumb for within meal keto carb thresholds:

  • Keto meals should, generally speaking, stay under 18 grams of carbs.
  • Keto snacks should have no more than 8 grams of carbs.

That’s total carbs, not net. Also, keep in mind that we don’t count above ground, non-starchy vegetables. Count the carbs in blueberries, not spinach. Count the carbs in beets, not kale. Count the carbs in carrots, not broccoli.

In my book, this is the easiest way to think of carbs on a keto diet. You don’t have to subtract fiber or weigh your romaine lettuce. You just count the carbs that, well, count.

There are contextual modifications, as we discussed earlier—exercise and activity levels, genetics/personal tolerance, keto adaptation status, previous meals.

And keep in mind just plain common-sense modifications:

  • If you’re eating one meal a day, you can get away with more carbs in that single meal than the person who eats 3 square meals and 2 snacks.
  • If you’re eating 3 meals and 2 snacks, you can’t get away with as many carbs as the person who eats one or two meals.

The more advanced you are, the more you can integrate your context into your decisions. This integration will happen intuitively, ideally. Then you can just eat and trust that your subconscious is keeping its end of the bargain.

If you’ve just finished a CrossFit WOD or gone bouldering for an hour or hiked up the local mountain, you’ve most likely incurred enough of a glycogen debt that a few extra carbs at your next meal won’t impact you keto status.

If you’re close to goal weight, you have steady energy all day, you can effortlessly skip meals, have a few wedges of watermelon at the birthday party that don’t affect you one way or the other… you’re probably reasonably fat-adapted and can handle a few more carbs per meal.

And through trial and error and simply doing the work and paying attention to what happens, you’ll learn your personal carb tolerance over time. Maybe in the near future we’ll even have high-powered data that can pinpoint your genetic carb tolerance to remove the guesswork.

But for the time being, especially if you’re just starting out with keto or find yourself staring at food labels in the grocery store aisle for a disproportionate amount of your life, “7-8 grams of carbs per snack and 16-18 grams of carbs per meal to stay keto” is a good rule of thumb.

What about you, folks? How many carbs do you limit yourself per meal to stay keto—or not?

TAGS:  Keto

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20 thoughts on “The Keto Carb Threshold: What Constitutes a “Keto” Meal?”

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  1. So I would not say I do keto necessarily. Most days I tend to eat lunch, snack, dinner. In a perfect world I would not snack but at 37 and working as a fitness director I get well over 20,000 steps a day and workout 3-4X a week. So I eat apples, squash, white rice some times and I would argue that I probably go into ketosis quite often.
    I do not weigh or measure anything (that just causes anxiety in my world).
    Most days it is a BAS for lunch with hardboiled eggs and a protein and veggies for dinner (salmon and broccoli tonight), my snacks are almost always a handful of almonds maybe with an orange.

    I generally feel great. I do not worry about ketosis at all. I am so damn active I think I just dip in and out knowing I can go until lunch or longer without food, and then try to eat as healthy as possible.

    Mark mentions this in the Keto Reset. So for me I do not think about it too much, generally feel awesome, and I am pretty certain from a subjective standpoint that I am keto adapted or if I am not I do not care as I feel damn good!

    Thanks for all you do Mark!

    1. Maybe I’m wrong, but I think your whole comment perfectly describes what Mark’s end goal is for people trying the keto reset. I hope I’ll get to that point someday not too far off.

  2. I need to lose weight and I am having a hard time as I have physical issues/limitations. I’ve been hearing great reviews about the keto diet but, I have read that it can affect your thyroid. As I have Hashimoto’s ,this is a huge concern for me. Is this diet safe for me? Will I get the same out of it as the someone who doesn’t have thyroid issues?

    1. I have complex thyroid issues and I have used it without problems. But I can’t give you medical advice about what to do in your case. I can only share what I’ve learned so far.

      I would point you to “Stop the thyroid madness” (the website STTM), and suggest that you do a lot of research on your own, especially about Reverse T3 and why doctors should be testing it. If it was me, I’d demand some kind of anti-inflammatory treatment, whether that’s natural curcumin or a cox-2 inhibitor drug. I don’t like the learned helplessness that current medical practice has around Hashi. Meaning, they don’t treat it and tell the patient to go lose weight.

      And I’d ask to be tested for Celiac Disease which is 10 times more prevalent than IBD but is rarely tested or suspected, but it should be, especially with other autoimmune issues. Gluten itself can directly affect the thyroid so after you’re tested for Celiac, then you can try gluten-free and see if it helps you (get the test first, they can’t accurately test you if you’re gluten free). One of the side effects of the primal keto diet is, that it’s also gluten free.

      Here’s why that helps: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5435852/

      Celiac, if you have the genetic predisposition, can trigger at any time and the risk of it becoming active rises as you get older, it might be a good idea to have a genetic test like 23andme (or its competitors) and know for sure if that’s a risk for you. Most services will tell you if you have those genes.

      My heart goes out to you because this issue is very complex and most of the time, people have to figure it out on their own. Doctors are siloed into “endocrinology” and “gastroenterology” and rarely put the puzzle pieces together to describe how one affects the other. But awareness is improving and it’s more likely that you’ll find a doctor who does see the connections and can give you targeted advice. If not, then seek out a concierge practice or a functional medicine MD. It took a functional medicine MD to finally figure out my thyroid issue. They take no insurance that’s how you recognize them, in the US. In the UK, that would be called “going private.”

    2. I have Hashimoto’s and lost weight going keto with no problem. Removing grains and bad fats from your diet removes inflammation and any autoimmune reactions you may be having to the grains.. Net result of it all is weight loss and feeling good!

  3. Question, so should the carbs be coming from below-ground vegetables like beets and onions and carrots, or if it falls under said carb amount per meal, does it matter if it comes from higher sugar fruits or from potatoes? My meals tend to be usually proteins and above ground vegetables, so I wouldn’t be counting any of those. For example I really like pink lady apples. The ones I buy state 16g carbs per apple. Having one of those with a meal would be fine? How about without a meal, would that be more likely to knock someone out of ketosis?
    Thanks for the general guidelines and different considerations as I am planning to participate in the June reset, if I can squander some food before the 3rd.

  4. I did full blown keto for 4 months and most days stayed at 40 – 50g or less. I lost 20 lbs and now I drift in and out of ketosis, keeping close to that number most days with ease. I maintain the weight, but if I have a day where I cheat, I just fast and everything normalizes within a few days.

  5. Thank you, this is just what I needed to feel unstuck, and was hesitant to ask the FB group, as they all sound so advanced. Thank you!

  6. Love your article, but after following a time consuming, every gram accounted for regime for 3 months ( yes i’m still losing weight) i still cannot get into ketosis at all! Therefore i fight constant hunger. I never exceed 20 carbs for the the day from all foods including weighing lettuce. HELP from anyone Please.

    1. Penny, if you are hungry you are not eating enough! Up your fats and maybe your protein, make sure you are satiated after a full meal.
      And relax. Relax in general, but relax about obsessive counting of macros. Stress makes everything much more difficult, affects sleep in a negative way, raises cortisol levels and so on. Relax. Remember that food is made by nature so it naturally varies in its nutrient content. You are not accounting for every gram, you are stressing about guesses!
      Get some decent recipes like Mark’s or from DietDoctor and prepare real food. Enjoy, relax and trust the process.
      Oh, one last thing: stop chasing ketones on a stick. The colour of a pee stick tells you nothing and the number on a blood ketone meter not much more. Go by body feeling. You feel good, have a healthy glow, are not hungry and lose weight? Great! Who gives a sh*t about the number on a screen when all real life indicators are showing success.

      1. Best advise ever
        I usually highlight some part of a comment and add to it, but I would need to paste the whole reply 🙂

    2. So, it strikes me that you almost certainly are in ketosis. If you are measuring your ketones with urine strips, know that they only indicate carbs that you are excreting. Once you are keto adapted, you will burn most ketones and not excrete them. If you want to know if you are in ketosis, you need either a blood meter or a breath meter. I recommend Ketomojo!

  7. I’m unclear as to why Mark says “don’t count above ground, non-starchy vegetables”. I mean, they have net carbs after you subtract the fiber. Surely a carb is a carb? I can easily eat 15 grams of carb per day in kale and broccoli alone; sometimes in a single meal..

  8. Not a reply but a request. I want to put on weight and gain muscle (fighting sarcopenia). I love fat and meat but have issues with cruciferous vegetables and fruit. When I stick to really low carb (30 carbs a day) i am constantly hungry even though I eat to saiety and the only things that satisfy me are bread and potatoes which more often than not I resist. Does Mark agree with cycling in/out of ketosis? I tried being practically no carb for two weeks and did not even approach ketosis according to the keto strips. I tried being strictly carnivore and felt really good but a voice in my head said you must eat vegetables so I feel good but worried !!

  9. @ Mary. Trust your body and your instincts. If you feel good on strict carnivore, why not stick to it. I strongly believe this is the natural diet of humans. I have been carnivore since August 1st, so almost a year now. The longer I follow the carnivore diet, the better I feel. I’m 42 years old and in the best shape of my life. Great article by the way Mark.

    1. More for Mary:

      “I tried being strictly carnivore and felt really good ”

      Same happened to my daughter, she has been carnivore for some time now

      I consider myself “low carb” (around 100g daily)
      In my case my one meal a day works perfectly, with raw liver almost daily (like one third of a cup with two egg yolks added)

  10. I’m surprised so few people actually weigh their food and calculate a proper 1:1 or 2:1 keto diet. I guess I had to do it because I was having migraines and PCOS. So I was treating medical conditions.

  11. The amount of carbs that will knock someone out of ketosis is different, but is there certain blood sugar number that will definitively mean a person is no longer in ketosis? Example if I eat something and my blood sugar rises to 105 am I still in ketosis? Compared to 110 or 130? Is there a tipping point?