Pecans vs walnuts: carbs, fiber and net carbs
Full comparison · Protein · Calories · Carbs
Per 3.5 oz (100 g), pecans has 12.7 g of carbohydrate (6.9 g net) and walnuts has 10.9 g (5.7 g net).
Net carbs = total carbohydrate minus fiber.
| Pecans | Walnuts | |
|---|---|---|
| Total carbohydrate, 100 g | 12.7 g | 10.9 g |
| Fiber, 100 g | 5.8 g | 5.2 g |
| Net carbs, 100 g | 6.9 g | 5.7 g |
| Total sugars, 100 g | — | — |
| Carbs per serving | 3.6 g in 1 oz (28 g) | 3.1 g in 1 oz (28 g) |
| Net carbs per serving | 2 g | 1.6 g |
Net carbs is total carbohydrate minus fiber; it is a common counting convention, not an FDA label term. Total sugars include natural and added sugar; USDA does not separate them for these foods.
What the numbers don't tell you
For the heart, the two come out close on cholesterol. Pooling 10 trials, pecans lowered LDL cholesterol by 7.42 mg/dL. Pooling 49 trials, walnuts lowered it by 5.68 mg/dL. Those are different trials, so the gap does not rank the nuts. Neither nut lowered blood pressure in pooled trials.
The real difference is the kind of fat. Per 3.5 oz (100 g), pecans carry about 39 g of monounsaturated fat against 10 g in walnuts, and walnuts carry about 49 g of polyunsaturated fat against 23 g in pecans. We hold no separate omega-3 figure.
For the brain, the one large trial is negative: two years of daily walnuts had no effect on cognition in 708 healthy adults aged 63 to 79. For pecans we hold only a single-meal test.
For banana bread we hold nothing on taste. Swap by weight, not cups: a cup of walnuts weighs 4.2 oz (120 g), a cup of pecans 3.5 oz (100 g).
Two cautions. Lab studies suggest the allergy proteins of both nuts survive heat, so baking does not make them safe for an allergic eater, and walnut and pecan allergy cross-react in one direction only. And the levothyroxine label names walnuts among foods that may reduce the drug's absorption, so if you take it, ask your pharmacist about timing.
Evidence behind this note
- Level A Pooling 10 randomized trials, pecan intake lowered LDL cholesterol by 7.4 mg/dL and total cholesterol by 8.5 mg/dL, with no change in HDL cholesterol. Diabetol Metab Syndr, 2026
- Level A Pooling 49 randomized trials with 4611 adults, walnut intake lowered LDL cholesterol by 5.7 mg/dL and total cholesterol by 6.4 mg/dL. Food Sci Nutr, 2026
- Level E Per 100 g, raw pecans carry about 39 g of monounsaturated fat against 9.6 g in walnuts, while walnuts carry about 49 g of polyunsaturated fat against 23 g in pecans. USDA FoodData Central, Foundation Foods, release 2026-04-30
- Level B Two years of eating walnuts every day did nothing for the thinking of healthy older people. Am J Clin Nutr, 2020
- Level B A 68 g pecan shake beat a saturated-fat control on 8 of 23 postprandial cognitive measures in 31 adults over 4 hours, while the control won on 3. Nutr Neurosci, 2025
- Level A Across 25 randomized trials with 2155 patients, walnuts lowered apolipoprotein B slightly but did not change blood pressure. Endocrinol Diabetes Metab, 2026
- Level A Across those same 10 trials of 4 to 12 weeks, the lipid gains came with no measurable change in blood sugar, body fatness or blood pressure. Diabetol Metab Syndr, 2026
- Level C Walnut and pecan cross-react in one direction only, which is why a walnut-allergic person cannot assume the same test result for pecans. J Allergy Clin Immunol Pract, 2021
- Level E The FDA-approved levothyroxine label names walnuts among foods that may bind the drug and reduce its absorption. DailyMed, levothyroxine sodium label f059a576-bb4b-441d-917e-4338bc3df403, effective 2026-03-24
- Level E A 1 oz (28 g) serving gives about 213 calories for unroasted pecans and 207 calories for walnuts, and a cup weighs 3.5 oz (100 g) for pecans but 120 g for walnuts. USDA Food and Nutrient Database for Dietary Studies (FNDDS), as loaded in FoodData Central 2026
- Level B In a controlled feeding trial on 18 adults, a 0.99 oz (28 g) serving of walnuts delivered 146 calories, 21% less than the 185 calories predicted by standard Atwater factors. J Nutr, 2016
- Level C A systematic review of 21 human and lab studies found nuts give less energy than labels predict, more so when raw and whole than roasted or as butter, but pecans were never measured. Adv Nutr, 2023
- Level D Roasting does not make pecans safer for a pecan-allergic person: the seed storage proteins that carry the allergy stayed heat stable across processing methods in a review of 32 studies. Allergy, 2013
Written from the studies and agency guidance we hold for both foods, reviewed by the Bioma editorial system. How we verify.
Keep exploring
Read more about these foods
- Pecans and walnuts: both lower LDL a little
- Pecans: a reliable cholesterol change and little else
- Walnuts: two years of daily walnuts did nothing for memory
What the studies say
Rankings and guides
- Carbohydrates: what it does and how much you need
- Fiber: what it does and how much you need
- Which foods are highest in dietary fiber?
- Which foods are highest in carbohydrate?
- Added sugar: what it does and what the evidence shows
- Pecans: full nutrition facts
- Walnuts: full nutrition facts
More comparisons
Where the numbers come from
- Pecans: USDA FoodData Central, Nuts, pecans, halves, raw, FDC ID 2346395 · full profile · all forms of pecans
- Walnuts: USDA FoodData Central, Nuts, walnuts, English, halves, raw, FDC ID 2346394 · full profile · all forms of walnuts
Each food is one USDA entry, chosen as it is usually eaten. Other cuts, brands and preparations differ; the links show them. % DV uses FDA Daily Values for adults. How we verify.