How many carbs are in walnuts?

Walnuts are about as low-carb as a snack gets. A 1 oz serving (28 g, ~14 halves) has only about 3.8 g of total carbohydrate — that’s 13.7 g per 100 g — and a good share of it is fiber, which doesn’t count toward blood sugar. Subtract the 1.9 g of fiber in that ounce and the net carbs land at roughly 2 g. That’s the lowest of the common nuts, and it’s the reason walnuts are a fixture on keto and low-carb plans.

Why the net carbs are so low

Net carbs are total carbs minus fiber, and walnuts start from a low total to begin with. Of the 13.7 g of total carbs per 100 g, about 6.7 g is fiber and only 2.6 g is sugar, with the rest mostly starch — so per 100 g the net carbs come out near 7 g, and at a realistic ounce you’re looking at only ~2 g net. Fiber is the carb you subtract because your body doesn’t digest it into glucose the way it does starch and sugar; combined with walnuts’ fat-forward profile — they’re the fattiest common nut — that’s why they read like a carb food on a label but barely register as one once the fiber comes out.

Why walnuts are a keto favorite

For keto, walnuts are near the top of the list. About 2 g net carbs an ounce uses almost none of a strict 20 g daily budget, and the macro shape is ideal: roughly 18 g of fat in that same handful means walnuts deliver fat with essentially no usable carbohydrate — exactly what a ketogenic plan is built around, with the omega-3 bonus other nuts don’t match. On low-carb plans generally, walnuts are one of the easiest snacks to fit, and their minimal glycemic impact means they won’t spike blood sugar the way a starchy snack would. The one thing to manage isn’t the carbs — it’s the calories, since at ~183 per ounce walnuts are the densest nut and a doubled handful adds up fast. Peanuts run a little higher on net carbs but bring more fiber per ounce; both are sound low-carb picks.

For the protein side of the same handful — and why walnuts carry protein rather than provide it — see protein in walnuts.