The keto diet is a high-fat, low-carb diet — but just how many grams of carbs per day is considered low enough?
Most people following a ketogenic diet will consume just 5-10% of calories from carbohydrates each day. If you’re eating 2,000 calories per day, this breaks down to 25–50 grams of carbs per day. (Don’t worry, you’ll dive into the math below).
This guide will help you determine how many grams of carbs per day to consume on keto. You’ll also learn how these amounts translate into various food sources (both good and bad).
But before you go any further, here’s one thing you should understand: Every human body is different. While 30 grams of carbs per day is a good rule of thumb for most people, the truth is that age, activity level, weight loss goals, and body composition play a role in determining how many carbs you can consume and stay in ketosis.
How to Calculate How Many Grams of Carbs Per Day
Knowing how many grams of carbs to eat per day on keto can be tough. Why? Because keto goes directly against the teachings of the Standard American Diet. In fact, the USDA and most dietitians advocate for a high-carb, low-fat diet to prevent weight gain, suggesting that 45-65% of total calories should come from carbohydrates[*].
On keto, you’re trying to transition to a fat burning metabolic state where you burn ketones — rather than glucose — as your body’s primary energy source. To do this, you’ll need to eat large amounts of fat, switch to moderate protein intake, and keep your daily carb intake to an absolute minimum.
To enter (and remain) in ketosis, the macronutrient guidelines for the average person include:
- 5-10% of calories from carbs
- 20-25% from protein
- 70-75%, or remaining calories from fat
How Many Carbs Do You Actually Eat on a Keto Diet?
A keto diet is generally made up of 70 to 75 percent fat, 20 to 25 percent protein, and 5 to 10 percent carbohydrates, says Jill Keene, a registered dietitian nutritionist in private practice in White Plains, New York. The exact number of grams (g) of carbohydrates will be different for everyone, but is generally around 20 to 50 g per day. Many people on a keto diet count “net carbs,” which is total carbs minus fiber. Fiber isn’t “counted” in the carbohydrate total, because it’s not digested. Either way, this number of carbs is very low and requires careful planning. Eating a little fruit, starchy vegetables, sugary foods, or whole grains can easily kick you out of ketosis.
If you’re on a keto diet, you know that staying and getting into ketosis (the whole goal of going keto), is achieved by eating a higher fat, moderate protein, and low-carb diet. You probably also know that the perfect amount of daily carbs is different for each person; some people can easily get into ketosis and stay there on 50 grams of toal carbs per day while others need to stay at around 20 grams of total carbs per day. So how do you determine the right amount of carbs for you? Read on to learn everything you need to know.
Carb Limits for Keto Beginners
The fact is, the amount of carbs you can tolerate and stay in ketosis depends on your particular body, how long you’ve been living keto, your exercise regime, and more. So, when you’re first starting a keto diet, it’s recommended to stick with 20 grams of net carbs per day or 20 grams of total carbs for therapeutic purposes. While 20 grams of total carbs is the amount that can get pretty much everyone into ketosis provided you eat within your daily macros, 20 grams of net carbs is the starting point for most people trying to achieve weight loss or general health benefits. To learn more about the difference between total carbs and net carbs, see below.
To ensure your body completely acclimates to the keto lifestyle, it’s recommended that you stick to 20 grams of net carbs per day for a full three months before you set out to explore your own personal carb edge.
Quick Net Carbs Primer
Net carbs are the total carbs minus the fiber (minus sugar alcohols if applicable). For example, a medium red bell pepper has 7 grams of total carbs and 2.5 grams of fiber. Therefore, the net carbs in a red bell pepper are 4.5. This is the number you would track to monitor your carb intake each day.
How to Determine if You’re in Ketosis
The best way to see if you’re in ketosis is to regularly test your blood using a blood-ketone testing meter. (For the most reliable results, be sure you follow the guidelines on exactly how to test and when to test.)
When you first embark on a ketogenic diet and begin testing your ketones, you’ll see your ketone levels start to rise from “Lo” to 0.1 mmol/L (the first measurable result) and higher. You’re in nutritional ketosis at 0.5 mmol/L.
Other signs your in ketosis can include some common (but temporary) discomforts known as keto flu symptoms. They’re common among people transitioning out of a high-carb diet and can include:
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- Fatigue
- Dizziness
- Nausea
- Brain fog
- Headaches
Meanwhile, your body may give other indications, too, including:
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- A slight fruity or acetone smell on your breath, also known as “keto breath”
- Increased energy (this typically happens once you’re in full ketosis)
- Decreased sugar cravings
- The ability to go longer between meals
How to Test Your Carb Limit
Once you’ve been steadily in ketosis for three months, you’re in a good position to test your carb edge, i.e. figure out whether you can tolerate more net carbs each day yet still stay in ketosis.
So that you don’t kick yourself out of ketosis or, if you do, you can recover quickly, it’s important to test your carb limit methodically. The best way to do this is to gradually increase your net carbs, test your ketones and glucose with your Keto-Mojo blood-glucose testing meter along the way, and stop when your test results come too close to pushing you outside of your optimal ketosis range.
Start by increasing your daily net carbs by 5 grams, so that your daily net carbs become 25 rather than 20. Stay at this increase for at least 3 days, testing to monitor your tolerance and ensure you remain in ketosis. If you get kicked out of ketosis, immediately dial back to 20 net carbs per day and know that you are already at your edge.
If you successfully stay in your desired range of ketosis on 25 net carbs per day for one week, bump your net carbs up to 30, try that for a week, and see how you fare.
Remember, we all have different carb tolerance. Some people easily get kicked out of ketosis when going above 20 grams of net carbs per day. Others can eat many more carbs yet remain in ketosis. Along with lifestyle, such as exercise, bio-individuality determines your carb edge. You can learn more about it from this quick, nifty video: Self Experimentation & Bio-Individuality on the Keto Diet
Step-By-Step Guide to Testing Your Carb Limit
Here are some easy to follow steps to help you determine your daily carb limit:
Day 1 through 3:
Increase your daily carbs by five net grams (i.e. from 20 to 25 grams), then test your ketones and glucose (see below for best times to test) to see how your body is responding. If your ketones drop significantly (and especially if they are below .5 mmol) and glucose rises more than 30 mg/dL after several hours, go back down to 20 grams of net carbs and know that 20 grams of net carbs are your daily limit.
If you remain in ketosis on 25 net grams of carbs per day (0.5 mmol or above, but ideally higher), stay at this level and continue testing for three full days. Ketone changes don’t show up as quickly as glucose does in test results, so this allows you time to ensure you’re truly still in ketosis before adding more carbs to find your edge.
Day 4 through 6:
If you’re still in ketosis at 25 net grams of carbs per day, Increase your daily net carbs by 5 grams again, so you’re daily net carb consumption is 30 grams of net carbs. Again, test your ketones and glucose to see how your body is responding as described above. If you continue to stay in ketosis throughout the day, continue consuming 30 net carbs per day for three days.
Three day increments:
If you’re still in ketosis at 30 net carbs per day, you can continue to increase your net carbs by 5 grams every three days until you reach your personal carb limit or “carb edge” (the amount of carbs you’re able to consume without getting kicked out of ketosis). Keep in mind that your ketosis levels can be affected by other factors as well (see below), so be sure to test your ketones and glucose frequently until you know for sure what your upper limit is.
The Best Time to Test
The best way to get the clearest results from testing your ketones and blood glucose is to test before you eat and 30 and 120 minutes after you’ve eaten and to be consistent about your testing times. (You can read more about the best times to test ketones and glucose here.) So, pick a time to test that works best for you, and try to be consistent with that same time each day. Then you can compare your results to the days prior at the same time. At a minimum, when determining your daily carb limit, you may want to test two hours after you wake up (while fasted) to get your baseline test result, and again two hours after meals.
