Wheat bread vs white bread: calories compared

Per 3.5 oz (100 g), whole wheat bread has 43.1 g of carbohydrate and 6.0 g of fiber, against 49.2 g and 2.3 g in white bread. The effect on blood sugar is small. A meta-analysis of 22 randomized trials found that breads higher in fiber, whole grain or added ingredients, eaten for at least two weeks, lowered fasting blood glucose by 3.8 mg/dL (0.21 mmol/L) against regular bread, which was not always white. The benefit sat mainly in people with type 2 diabetes, and HbA1c, the three-month marker, showed no clear change.

At a single meal, in 121 people with type 2 diabetes, 3.5 oz (100 g) of whole wheat bread raised blood glucose over two hours about as much as white bread. Cohort studies link whole grains in general, not bread alone, with 32 percent lower type 2 diabetes risk per 3 servings a day, a link, not proof of cause.

In short tests, low-phytate white bread raised blood iron more over two hours than high-phytate whole wheat, which is not the same as better iron stores. White bread here lists more iron (3.36 vs 2.56 mg per 3.5 oz (100 g)).

Pick whole wheat for about 2.6 times the fiber, not as a blood sugar treatment. If a doctor has put you on a diet for diabetes, follow that plan first.

Per 3.5 oz (100 g) the two breads are close, 254 calories for whole wheat and 270 for white. Slices differ, though. A medium slice of US whole wheat bread weighs 1.3 oz (36 g), about 91 calories, while a medium slice of white weighs 1 oz (28 g), about 76. The slices in the table above, 1.1 oz (32 g) and 1 oz (27 g), come to about 82 and 74 calories. Count slices by weight if you track calories.

Evidence behind this note

1. Level A Across 22 randomized trials in 1037 adults, healthy or at cardiometabolic risk or with type 2 diabetes, eating reformulated breads (more fiber, whole grain or functional ingredients) instead of "regular" or comparator bread, not always white, for at least 2 weeks lowered fasting blood glucose by 3.8 mg/dL (0.21 mmol/L), with trials varying widely and the effect concentrated in the type 2 diabetes subgroup, and HbA1c showed no clear change. Adv Nutr, 2023
2. Level B In 121 people with type 2 diabetes, 3.5 oz (100 g) of whole wheat, wheat bran or rye bread raised blood glucose over 2 hours about as much as 3.5 oz (100 g) of white bread (P = 0.093), so a darker loaf is not automatically a lower-sugar one. Diabetes Res Clin Pract, 2008
3. Level C Pooled cohort data link refined grains, the group white bread belongs to, with no clear change in type 2 diabetes risk (relative risk 0.95 per 3 servings a day), while whole grains in the same observational data were linked with 32% lower risk, and white bread was not analyzed on its own. Eur J Epidemiol, 2013
4. Level B A systematic review of 8 human studies found that low-phytate white bread raised serum iron more over 2 hours than high-phytate whole wheat bread (59 vs 30 mcg/100 mL), a short-term rise that is not the same as better iron stores, since longer trials found no ferritin gain, and no properly controlled human study shows that sourdough fermentation improves iron status. Front Nutr, 2026
5. Level E A medium slice of US whole wheat bread weighs 1.3 oz (36 g) and carries about 2.2 g fiber, 155 mg sodium and 9 ug selenium. USDA FNDDS (FoodData Central survey), Bread, whole wheat, food code 51300110, fdc_id 2707709
6. Level E A medium slice of white bread weighs 0.99 oz (28 g) in the US survey database (thin 24 g, thick 43 g), which at the US table values gives about 76 calories, 13.8 g carbohydrate and 134 mg sodium per slice. USDA FNDDS food 2707598 portions and FoodData Central record 325871

Written from the studies and agency guidance we hold for both foods, reviewed by the Bioma editorial system. How we verify.

Read more about these foods

• Wheat bread: what switching to whole grain changes
• White bread: what the swap trials found

Rankings and guides

• Calories: what it does and what the evidence shows
• Which foods give the most protein for the fewest calories?
• Dietary fat: what it does and how much you need
• Wheat bread: full nutrition facts
• White bread: full nutrition facts

• Wheat bread: USDA FoodData Central, Bread, whole-wheat, commercially prepared, FDC ID 335240 · full profile · all forms of wheat bread
• White bread: USDA FoodData Central, Bread, white, commercially prepared, FDC ID 325871 · full profile · all forms of white bread

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.