Is Peanut Butter Keto-Friendly? What to Check Before You Buy

How Many Carbs Are in Peanut Butter?

The peanut butter rows come from USDA FoodData Central’s entry for smooth peanut butter without salt; the salted version lists the same carbohydrate and fiber. The last row is USDA’s dry-roasted peanuts without salt, weighed to match two tablespoons. Net carbs are total carbohydrate minus fiber, worked out before rounding, so a row can be a tenth of a gram off if you subtract the rounded numbers yourself.

Two tablespoons is the line to remember: 7.1 grams of carbohydrate, but only 1.6 grams of that is fiber, so about 5.5 grams of net carbs are left. That is a good deal more than an ounce of pecans, which comes to about 1.2 grams in our pecans guide, because peanut butter starts with more carbohydrate and has less fiber to take off it.

The peanut row is there because a jar of only peanuts and salt is, quite literally, ground roasted peanuts. USDA’s peanut butter entry carries less fiber than the peanuts do, so a peanuts-and-salt jar may well come in nearer the peanut row than the smooth ones. A sweetened jar goes the other way. Either way, its label rounds to whole grams and uses its own serving size, so for a particular jar, go by its label.

What none of these figures can tell you is whether a spoonful “keeps you in ketosis.” That depends on everything else you eat in a day, not on one ingredient, so use the table to see how much room peanut butter takes up rather than as a pass or fail.

Natural, Regular and Powdered Peanut Butter

In the U.S., peanut butter has a fairly strict recipe. Under FDA’s standard for peanut butter, everything added to the ground roasted peanuts, the salt, sweetener and stabilizing oil together, can’t come to more than 10 percent of the jar. Artificial sweeteners aren’t allowed at all, and the only oil allowed as a stabilizer is a hydrogenated one.

So most of what separates one jar of peanut butter from another sits in that last 10 percent, and the ingredient list tells you what’s in it.

“Natural” on the front of the jar settles less than it sounds like it should. FDA has never formally defined the word for food labels, so a jar sold as natural can still have sugar in it. The ingredient list is what tells you, not the front.

The same goes for a jar called “peanut butter spread.” It doesn’t meet the peanut butter standard, which means something in it does what the standard doesn’t allow: more added ingredients than the 10 percent, an oil that isn’t hydrogenated, or a sweetener the rule excludes. None of that makes it off limits, but it is the jar whose ingredient list most needs reading.

Powdered peanut butter is the odd one out. It is roasted peanuts pressed to remove most of their oil and ground into a powder, and since it is the fat that goes, carbohydrate makes up a bigger share of what’s left. Some brands add sugar and salt as well. As far as a recipe is concerned it isn’t peanut butter in another form, because the fat is gone, and none of our recipes is written for it.

What to Check on the Label

Four things on the jar tell you what you’re buying, in no particular order:

• The Added Sugars line. On the Nutrition Facts panel, the “Includes … Added Sugars” line sits under Total Sugars, and it is required on the label. Any amount above zero tells you sugar was added, but 0 g doesn’t prove nothing did: less than half a gram per serving can be rounded down to zero on the label. So use it as a first check and let the ingredient list settle it. Total Sugars can still show a gram or two, because peanuts carry a little sugar of their own.
• The ingredient list. Peanuts first, and ideally only salt after them. Sugar, honey, molasses, corn syrup or dextrose means the jar is sweetened, whatever the front says and whatever the Added Sugars line rounds to.
• The name. “Peanut butter” means the jar meets the standard above. “Peanut butter spread” means it doesn’t, for one reason or another.
• The serving weight. The serving is usually two tablespoons, with its weight in grams beside it. When two jars list different weights, compare their carbs gram for gram rather than spoon for spoon.

An added oil, hydrogenated or palm, doesn’t put any carbohydrate in the jar. It is there to keep the peanut oil from separating, so it tells you what kind of jar you have rather than changing the carb count.

How Much Is Two Tablespoons?

The carb table is for level tablespoons, and peanut butter is very easy to heap. A spoon dragged through the jar comes out rounded, not level, and going back for a little more is how two tablespoons quietly becomes three.

So measure it the first few times you use a new jar. A tablespoon scraped level with a knife is the simplest way. With a kitchen scale, USDA’s weight is 16 grams to the tablespoon, and weighing it saves you from scraping something this sticky out of a measuring spoon.

Two tablespoons also carry about 190 calories, most of them from fat, according to the same USDA entry. That is worth knowing if carbs aren’t the only thing you keep track of.

How Our Recipes Use Peanut Butter

Most of our peanut butter recipes never go near the oven, and in nearly all of them the peanut butter is mixed with a little fat and a sweetener rather than used straight from the jar. Several use a powdered sweetener, which the fudge recipe chooses because it mixes in smoothly without leaving the fudge grainy.

No-bake treats

The peanut butter fat bombs and the double-stuffed peanut butter cups are both chocolate and peanut butter set in small cups, and the difference is where the peanut butter goes. The fat bombs warm it for a few seconds and drop it into the coconut-oil chocolate, so it marbles through. The cups whip it with softened butter and powdered sweetener into a filling, and seal it between two layers of chocolate.

The peanut butter balls and the cocoa peanut butter truffles are rolled instead. The balls are peanut butter, melted butter and powdered monk fruit, frozen firm and then dipped in melted chocolate. The truffles mix it with heavy cream, sweetener and a little cocoa, and get rolled in more cocoa before an hour in the freezer.

The peanut butter fudge is the one that gets cooked on the stove. Cream, butter and sweetener cook down until they thicken and turn golden, and the peanut butter is whisked in off the heat while the mixture is still hot. The peanut butter rice krispie treats melt the peanut butter in a saucepan with butter and sugar-free honey, then pour it over a frosted protein cereal. That is the pour in the photo at the top of this page.

Baked: the cupcakes

The peanut butter frosted cupcakes are the only one of these recipes that goes in the oven, and even there the peanut butter stays out of it. The cake is a plain vanilla cupcake made with almond and coconut flour, and the peanut butter is all in the frosting, beaten with butter, vanilla, powdered sweetener and a little cream until it goes light.

In a chaffle

The peanut butter chaffle does something similar. Two small chocolate chaffles, with no cheese in them, are cooked in a mini waffle maker and sandwiched around peanut butter whipped with heavy cream and powdered sweetener. It won’t whip into stiff peaks, and the recipe doesn’t expect it to.

How much peanut butter is in a serving

Here is the peanut butter in each recipe, straight from its recipe card, along with roughly how much ends up in one serving.

Every serving except the chaffle has less than a tablespoon of peanut butter in it, under the first row of the carb table. The peanut butter is only one ingredient, though, so for what a whole serving adds up to, with the chocolate, cream and sweetener counted in, use the Nutrition Facts panel on each recipe.