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Low carb bread, measured with USDA generic data, starts with the lightest slices: USDA FoodData Central lists a 19-gram slice of protein bread at about 8.3 grams of total carbohydrate and a 21-gram slice of reduced-calorie wheat bread at about 8.9 grams, against about 14.3 grams for a 29-gram slice of white bread. Most loaves sold as low carb are brand products with their own recipes, and USDA generic data cannot describe them, so their Nutrition Facts label is the number that counts. The table below ranks 22 USDA generic bread entries by total carbohydrate per slice, with FDC IDs, the FDA percent Daily Value, fiber and calories.
Peptide Labs does not sell foods. This article is general nutrition information, not medical advice.
Key Takeaways
- In USDA data the slices with the least carbohydrate are the lightest: protein bread at 8.3 grams per 19-gram slice, reduced-calorie wheat at 8.9 grams and reduced-calorie rye at 9.3 grams.
- Per 100 grams, USDA bread entries run from about 33.9 grams to 52.8 grams of carbohydrate, so slice weight does much of the ranking.
- Under the FDA rule 21 CFR 101.60, a reduced-calorie claim means at least 25 percent fewer calories than the reference food; it says nothing about carbohydrate.
- The FDA Daily Value for total carbohydrate is 275 grams, and FDA's claim rules define 'high' and 'good source' for fiber but not for total carbohydrate.
- For brand loaves marketed as low carb, check the Nutrition Facts label for total carbohydrate, dietary fiber and slice weight.
Low carb bread ranked by USDA carbohydrate per slice
The table uses USDA SR Legacy generic bread entries, one slice at the gram weight USDA assigns to each. Carbohydrate is total carbohydrate, which the FDA label rule (21 CFR 101.9) calculates by subtracting protein, fat, moisture and ash from the food’s weight; the percent Daily Value (%DV) uses the FDA Daily Value of 275 grams, and the last column compares USDA entries per 100 grams.
| Bread (USDA FDC ID) | Slice | Carbohydrate | % DV | Fiber | Calories | Carb per 100 g |
|---|---|---|---|---|---|---|
| Bread, protein (includes gluten) (174917) | 1 slice, 19 g | 8.3 g | 3% | 0.6 g | 47 | 43.8 g |
| Bread, reduced-calorie, wheat (174921) | 1 slice, 21 g | 8.9 g | 3% | 2.3 g | 46 | 42.5 g |
| Bread, reduced-calorie, rye (174920) | 1 slice, 23 g | 9.3 g | 3% | 2.8 g | 47 | 40.5 g |
| Bread, reduced-calorie, white (174922) | 1 slice, 23 g | 10.2 g | 4% | 2.2 g | 48 | 44.3 g |
| Bread, multi-grain (includes whole-grain) (168013) | 1 slice, 26 g | 11.3 g | 4% | 1.9 g | 69 | 43.3 g |
| Bread, rice bran (174923) | 1 slice, 27 g | 11.7 g | 4% | 1.3 g | 66 | 43.5 g |
| Bread, gluten-free, whole grain (made with tapioca and rice flour) (174102) | 1 slice, 25 g | 12.3 g | 4% | 1.2 g | 77 | 49.1 g |
| Bread, white wheat (167532) | 1 slice, 28 g | 12.3 g | 4% | 2.6 g | 67 | 43.9 g |
| Bread, pumpernickel (174918) | 1 slice, 26 g | 12.3 g | 4% | 1.7 g | 65 | 47.5 g |
| Bread, cracked-wheat (172672) | 1 slice, 25 g | 12.4 g | 4% | 1.4 g | 65 | 49.5 g |
| Bread, wheat, sprouted (171850) | 1 slice, 38 g | 12.9 g | 5% | 2.0 g | 71 | 33.9 g |
| Bread, oatmeal (172678) | 1 slice, 27 g | 13.1 g | 5% | 1.1 g | 73 | 48.5 g |
| Bread, raisin, enriched (172680) | 1 slice, 26 g | 13.6 g | 5% | 1.1 g | 71 | 52.3 g |
| Bread, whole-wheat, commercially prepared (172688) | 1 slice, 32 g | 13.7 g | 5% | 1.9 g | 81 | 42.7 g |
| Bread, wheat (172686) | 1 slice, 29 g | 13.8 g | 5% | 1.2 g | 79 | 47.5 g |
| Bread, Italian (174913) | 1 slice, 29 g | 14.0 g | 5% | 0.6 g | 75 | 48.1 g |
| Bread, white, commercially prepared (174924) | 1 slice, 29 g | 14.3 g | 5% | 0.8 g | 77 | 49.4 g |
| Bread, potato (167943) | 1 slice, 32 g | 15.1 g | 5% | 2.0 g | 85 | 47.1 g |
| Bread, rye (172684) | 1 slice, 32 g | 15.5 g | 6% | 1.9 g | 83 | 48.3 g |
| Bread, gluten-free, white (made with rice flour) (174099) | 1 slice, 34 g | 18.0 g | 7% | 1.2 g | 109 | 52.8 g |
| Bread, egg (172673) | 1 slice, 40 g | 19.1 g | 7% | 0.9 g | 115 | 47.8 g |
| Bread, Boston brown, canned (174907) | 1 slice, 45 g | 19.5 g | 7% | 2.1 g | 88 | 43.3 g |
Three groups stand out in USDA data. The protein and reduced-calorie entries lead because their USDA slices weigh 19 to 23 grams; pumpernickel, cracked-wheat, white wheat and multi-grain follow at about 11 to 12.5 grams per slice in USDA data; whole-wheat, wheat, Italian, white, potato and rye bread sit at 13.7 to 15.5 grams, and the heaviest USDA slices, gluten-free white, egg and canned Boston brown bread, pass 18 grams. Sourdough bread appears in USDA only inside the French or Vienna entry, at about 51.9 grams of carbohydrate per 100 grams, and USDA lists oat bran bread at about 39.8 grams per 100 grams.
Lowest carb bread: why USDA slice size sets the ranking
Per 100 grams, USDA bread entries sit in a narrow band, from about 33.9 grams of carbohydrate for sprouted wheat bread to 52.8 grams for gluten-free white, with white bread at 49.4 grams and whole-wheat at 42.7 grams. USDA slices range from 19 to 45 grams, which is why sprouted wheat, lowest per 100 grams, lands mid-table: USDA weighs its slice at 38 grams. A 20-gram USDA thin slice of pumpernickel is about 9.5 grams of carbohydrate.
For a packaged loaf, the FDA label rule (21 CFR 101.9) requires a serving size in a household measure with its gram weight, and its own example for sliced bread is “1 slice (28 g/1 oz)”, so the label shows both the slice weight and its carbohydrate. Our bagels, pita, naan and tortillas guides apply the same USDA approach to breads that are not sliced loaves.
Carbs in a slice of bread: what the reduced-calorie entries show
In USDA data the reduced-calorie entries hold about 9.7 to 12 grams of fiber per 100 grams, against 2.7 grams for white bread and 6.0 grams for whole-wheat, and their slices weigh 21 to 23 grams. Measured that way, the carbs in bread of this type come to about 8.9 to 10.2 grams per USDA slice, about 3% to 4% of the FDA Daily Value.
The claim words on such loaves have FDA definitions. Under 21 CFR 101.60, “reduced calorie”, “fewer calories” or “lower calorie” means at least 25 percent fewer calories per reference amount than an appropriate reference food, with the reference food and the difference declared next to the claim; under 21 CFR 101.56, “light” on a food that gets less than half its calories from fat means calories cut by at least one-third or fat cut by half or more. Neither FDA rule mentions carbohydrate, so the carbohydrate figure still comes from the label.
What FDA label rules say about carbohydrate claims
Read as written, the FDA section that defines “high”, “good source” and “more” claims (21 CFR 101.54) applies to nutrients with a Daily Value “excluding total carbohydrates”, and the FDA sections that define “low” claims cover calories and sugars (101.60), sodium (101.61) and fat-related terms (101.62). FDA requires the Nutrition Facts label to list total carbohydrate, dietary fiber, total sugars and added sugars. Our low carb foods guide covers net carbs arithmetic that labels do not print, and our refined carbs guide covers what refining removes from grain.
Fiber claims, by contrast, are defined. Under 21 CFR 101.54, “high” or “excellent source of” fiber means 20 percent or more of the FDA Daily Value of 28 grams per reference amount and “good source” means 10 to 19 percent, and under the same FDA rule a fiber claim on a food that is not low in fat must disclose the total fat per serving next to the claim. FDA counts as dietary fiber the fiber that is intrinsic and intact in plants plus isolated or synthetic non-digestible carbohydrates it has accepted, a list that has grown since the 2016 label rule to include acacia (gum arabic) in 2021, which matters for loaves made with added fibers.
Whole wheat, multigrain, sprouted and rye: reading the USDA entries
- Whole-wheat versus white: USDA lists 42.7 versus 49.4 grams of carbohydrate per 100 grams, but the whole-wheat slice weighs 32 grams against 29, so per USDA slice the gap narrows to 13.7 versus 14.3 grams.
- Multi-grain: the USDA entry pools multi-grain and whole-grain loaves; FDA’s draft whole grain guidance considers a grain whole when the endosperm, germ and bran are present in the same proportions as in the intact kernel, so the ingredient list, not the word multigrain, shows whether a loaf’s grains are whole.
- Sprouted wheat: USDA’s entry is the lowest per 100 grams, 33.9 grams of carbohydrate, and the highest in protein per slice, 5.0 grams, but its 38-gram slice puts it mid-table.
- Rye and pumpernickel: USDA lists 48.3 and 47.5 grams per 100 grams, close to white bread; pumpernickel ranks higher only because its USDA slice weighs 26 grams against 32 for rye.
- Enriched white bread: under the FDA standard of identity (21 CFR 136.115), enriched bread must contain set amounts of thiamin, riboflavin, niacin, folic acid and iron per pound.
Loaves marketed as low carb: why USDA cannot rank them
USDA SR Legacy carries generic entries, not brand recipes, and loaves marketed as low carb are brand products built from ingredients such as gluten, added fibers, seeds and nut flours in proportions USDA does not record. The nearest generic entry, USDA’s protein bread (includes gluten), lists 43.8 grams of carbohydrate per 100 grams, so its low slice figure comes mostly from a 19-gram USDA slice. For any such loaf, read the Nutrition Facts label for total carbohydrate, dietary fiber and slice weight, and the ingredient list for added fibers. Our foods with gluten guide covers gluten, and our high carb foods guide places bread among other grain foods.
Frequently Asked Questions
Which bread has the fewest carbs per slice in USDA data?
USDA’s protein bread entry, at about 8.3 grams of carbohydrate per 19-gram slice, then reduced-calorie wheat at 8.9 grams and reduced-calorie rye at 9.3 grams in USDA data.
How many carbs are in a slice of white bread?
About 14.3 grams of total carbohydrate in a 29-gram USDA slice of commercially prepared white bread, 5% of the FDA Daily Value of 275 grams.
Is whole wheat bread lower in carbs than white?
Per 100 grams yes in USDA data, 42.7 versus 49.4 grams; per USDA slice the gap narrows to 13.7 versus 14.3 grams.
Does FDA define a low carb claim?
The FDA sections that define ‘low’ claims cover calories and sugars, sodium and fat, and the FDA section for ‘high’ and ‘good source’ claims excludes total carbohydrates.
Can USDA data describe a brand low carb loaf?
No. USDA SR Legacy holds generic entries only, so the Nutrition Facts label and ingredient list are the sources for a brand loaf’s carbohydrate, fiber and slice weight.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a health condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Low Fiber Foods: USDA Fiber per Serving, Ranked Low to Higher, Refined Carbs vs Whole Grains: Simple and Complex Carbs Explained, Sourdough Bread: Nutrition, Gluten and Is It Healthy?, Rye Bread: USDA Nutrition per Slice, Research and How It Compares.