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

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

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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