Everyone—and we really mean everyone—is trying keto right now. But despite the diet’s wild popularity, there’s still some debate about how to do it right. Here, we break down the macro mix, which isn’t as cut and dry as you might think.
The Goal Of Keto
The basis of the ketogenic diet is to shift your body into ketosis, a state in which it uses fat for energy instead of carbs and sugar. The resulting benefits include weight loss, increased energy, and reduced cravings.
To get there, though, you have to deprive your body of its primary fuel source, glucose (which it breaks carbs and sugar down into). That means virtually all carbs are off the table. You also have to limit protein, which your body can turn into glucose when desperate.
To make up for the lost calories, you need to eat fat (and lots of it!), which your body uses to produce an alternative form of fuel called ketones.
Why Macros Matter
Sounds like tricky business, right?
While your average low-carb diet may allow for up to 20 percent of your daily calories to come from carbs (that’s about 120 grams), keto requires keeping carbs much, much lower, explains Monica Auslander Moreno, M.S., R.D., L.D.N., nutrition consultant for RSP Nutrition.
Eating even just a hair too much carbs or protein can throw you out of ketosis, so going keto requires paying incredibly close attention to how much of each macronutrient (a.k.a. carbohydrates, fats, and protein) you eat.
The Average Keto Macros
For most people, getting into ketosis requires eating 60 to 70 percent of their daily calories from fat, 15 to 30 percent from protein, and 5 to 10 percent from carbs, says Auslander Moreno.
For someone eating 2,000 calories per day, that’s 1,200 to 1,500 calories from fat, 300 to 600 calories from protein, and just 100 to 200 calories from carbs.
Another way to look at it: 133 to 166 grams of fat, 75 to 150 grams of protein, and 25 to 50 grams of carbs. (Fat contains nine calories per gram, while carbs and protein contain four.)
Often, dieters have to follow these macros for a week or two before their bodies transition into ketosis.
The Total Carb-Net Carb Debate
Sounds straightforward enough, right? Not so fast. You see, there are two ways to look at carbs—and some keto enthusiasts debate which measurement matters most.
First, you’ve got ‘total carbohydrates,’ which refers to the total grams of all carbohydrates consumed—including fiber, says Auslander Moreno.
Then you’ve got ‘net carbs,’ which refers to total grams of carbohydrates minus grams of fiber.
Most keto eaters insist that tracking total carbohydrates is the way to go, while others believe you can just track net carbs and essentially ignore fiber.
Though fiber is technically a carb, “it’s ‘indigestible,’ which means it doesn’t theoretically contribute to ‘energy intake,’” says Auslander Moreno. “The ‘net carb’ theory says that since fiber is indigestible, you can subtract the grams of fiber you consume each day from the amount of carbs you consume each day,” she explains. “But to imply that fiber grams negate carb grams is wrong.”
Thing is, the fiber you consume is anything but ignorable. Not only does fiber nourish the microbiome and help keep your digestive system moving and grooving, but it also promotes satiety, balances blood sugar, and supports healthy cholesterol levels.
That’s why Moreno—like many nutrition experts—recommends tracking total carbs when trying to get into ketosis. That means sticking to 25 to 50 grams of total carbs a day, fiber and all.
That doesn’t mean you should avoid eating fiber, though! Most experts recommend adults get at least 25 to 35 grams of fiber every day—keto or not.
Finding YOUR Ideal Keto Macros
Though the general keto macro framework above is a good starting point, it isn’t necessarily the end-all-be-all.
In a perfect world, you’d test your urine’s ketone levels daily and experiment with your macros to determine the highest threshold of carb intake you can get away with without shifting out of ketosis. How many carbs you can handle without shifting out of fat-burning mode depends on a few factors, like your body’s natural metabolism, how long you’ve been on keto, and how active you are.
Ketone levels between 1.5 and three mmol/L (referred to as ‘deep ketosis’), are recommended for maximum weight loss, explains Joshua Axe, D.N.M., D.C., C.N.S. However, you’ll still reap many of keto’s benefits with levels between 0.5 and 1.5 mmol/L (considered light nutritional ketosis).
When You Can Eat More Carbs On Keto
In any of the following apply to you, you may be able to up your carb intake without sabotaging your fat-burning.
1. If You’ve Been Keto-ing For A While
“When someone first starts a keto diet, they need to be especially strict in keeping carb intake low,” says Axe. He recommends sticking as close to five percent of your daily calories as possible in those first weeks and months.
“However, once the body gets use to burning fat for energy, you can often increase your intake up to 10 percent, and then maybe up to even 15 percent,” he says.
2. If You’re Training Hard
Certain types of exercise, like intense lifting, rely on sugar stored in your body (called glycogen) for fuel. When you severely limit your carb intake, though, your body turns to a process called gluconeogenesis (in which it breaks down protein to produce glucose) to fuel exercise.
However, this last-resort energy production method isn’t very efficient, says Jessica Crandall Snyder, R.D.N., dietitian at VitalRD. Not only will your performance likely take a hit, but you may also lose muscle mass over time. (Where do you think your body gets the protein for gluconeogenesis?)
Given that, keto dieters may want to consume some carbs before and after this type of training. While it may temporarily affect your ketosis to some degree, it’s worthwhile if training hard and maintaining muscle are top priority for you. Just keep those carbs low the rest of the day to support fat-burning.
The Bottom Line
Ultimately, the keto macro formula that works best for you depends on your lifestyle and where you are in your keto journey. Working with a dietitian can ensure you make any necessary adjustments and meet your nutritional needs.