Should You Be Focusing On Net Carbs Or Total Carbs? We Dig In

Walking through my local grocery store last week, I passed by the aisle with protein bars, granola, and generally healthy-ish snacks, and something caught my attention—a giant "keto-friendly" cookie that proudly proclaimed it had just 3 grams of net carbs on the front of the package. Cool, I thought, I like cookies and I'd rather not jack up my blood sugar.

But flipping over the package revealed that this seemingly innocent cookie had 26 grams of total carbs. What gives?

According to the company, most of those carbs come from allulose—a type of sugar alcohol—which means it basically "doesn't count," as your body can't metabolize it like regular sugar, and some of those carbs come from fiber, which isn't absorbed, so that "doesn't count" either. At least that's what several companies marketing their products to low-carb, keto dieters are claiming. But honestly, it seems too good to be true.

"Net carbs," sometimes referred to as "impact carbs" or "active carbs," isn't a legally defined term. The only type of carb regulated by the Food & Drug Administration is the total carbs you see on the nutrition facts, which is broken down into dietary fibers and sugar.

But what's the point of this calculation? The basic concept is that not all carbs are equally absorbed by the body—and thus, they shouldn't be counted. These uncounted carbs are sometimes referred to as "non-impact carbs" or "inactive carbs."

"One upside to looking at net carbs is that you get an idea of how that particular food might impact your blood sugar, which ties in to how long you feel full and energized," says Jess Cording, R.D., mbg Collective member. For example, a slice of bread1 and a cup of raspberries2 have an equal number of total carbs (15 grams), but the raspberries will keep you fuller and happier because they pack significantly more fiber (8 grams vs. 0.8 grams), giving them a lower net carb count (7 grams vs. 14.2 grams).

The short answer: yes, several. Miller feels quite strongly that focusing on only net carbs isn't an accurate measure of carb intake because the way each individual processes and metabolizes "non-impact" carbs like fiber is different.

"In my 10-plus years of using the ketogenic diet for beneficial metabolic, hormonal, and neurological influences on the body, I have always stuck with total carbs because there are variances in our individual blood sugar responses to fibers, depending on the unique state of our gut bacteria and blood sugar metabolism," she says. "Also, the form of fiber (soluble vs. insoluble) may be metabolized differently, and the source of the fiber in many packaged foods is highly processed and could still yield a blood sugar spike."

And while the net carb formula is likely flawed across the board, it's probably the least useful when it comes to packaged foods. At least with a whole plant food like raspberries, you know that the low net carb number is a result of naturally high fiber content—which is awesome for your health for a number of reasons. But with packaged foods, these added fibers and sugar alcohols are not something your body typically encounters (at least not in such high quantities), which can lead to its own set of issues.

"As soon as the food industry caught on to the value of fiber, they started adding processed industrialized ingredients to packaged foods to increase the total fiber count, but many of these ingredients can be gut irritants," says Miller. "I always say focus on whole food ingredients—the impact of the fiber from leafy greens, avocado, nuts, and seeds is superior to that in a processed product using inulin, corn fiber, or other additives."

"Net carbs are a misleading and potentially an inaccurate way to monitor carb intake," says Miller, and neither Cording nor Miller recommends that anyone (including low-carb keto dieters) use them to track carb intake.