Potato bread: the trials used a different loaf

The best evidence on potato bread comes from China, and it tested a steamed potato-wheat bread, a different food from the soft sandwich loaf sold as potato bread in the United States. In a randomized trial of 79 adults eating it at lunch for 4 weeks, weight fell by 1.3 lb (95% CI 0.22 to 2.6; metric: 0.6 kg, 0.1 to 1.2) and LDL cholesterol by 8.5 mg/dL (95% CI 0.39 to 19; metric: 0.22 mmol/L, 0.01 to 0.49) compared with plain wheat bread. It was a small trial at one site, and the LDL result sits at the edge of significance. A school trial that randomized four whole classes of Chinese teenagers ran for 8 weeks. Potato bread lowered insulin by 4.35 mIU/L and raised systolic blood pressure by 4.6 mmHg against wheat bread, with 69 percent boys in the potato group and 39 percent in the control. The US loaf itself has 266 calories, 6.3 g fiber, 9.4 g sugars and 375 mg sodium per 3.5 oz (100 g), from a single FNDDS value for recipes that vary.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• US potato bread has 266 calories, 47.1 g carbohydrate, 12.5 g protein, 6.3 g fiber, 9.4 g total sugars and 375 mg sodium per 3.5 oz (100 g). — FNDDS food code 51127010, Bread, potato Evidence E source
  Per 100 g: 266 calories, carbohydrate 47.07 g, protein 12.5 g, fiber 6.3 g, total sugars 9.38 g, sodium 375 mg

What a real portion looks like

• A medium slice of US potato bread weighs 1.2 oz (34 g) and carries about 90 calories, 16 g carbohydrate and 128 mg sodium. — FNDDS portions for Bread, potato: small slice 26 g, medium 34 g, large 43 g Evidence E source
  Medium slice 34 g: 90.4 calories, carbohydrate 16.0 g, protein 4.2 g, fiber 2.1 g, sodium 127.5 mg; large slice 43 g: 114 calories

What your body absorbs

• In a laboratory digestion model, replacing 15% of wheat flour with potato flour raised resistant starch in bread from 5.2% to 11.3% and lowered estimated glycemic index from 95 to 87. — wheat breads with 0 to 15% potato flour, in vitro starch digestion, not people Evidence D source
  Resistant starch 5.2% to 11.3%; estimated GI 95 to 87

What cooking and storage change

• Toasting potato bread drives off water, so 3.5 oz (100 g) of toast has 292 calories against 266 calories untoasted, while a medium slice stays at about 90 calories. — FNDDS Bread, potato, toasted (FDC 2707643) vs Bread, potato (FDC 2707642) Evidence E source
  Per 100 g: 292 vs 266 calories, carbohydrate 51.72 vs 47.07 g, sodium 412 vs 375 mg; medium slice 31 g toasted vs 34 g untoasted, both about 90 calories

What it does to your health

• In a cluster-randomized trial in Chinese adolescents, eating steamed potato bread every school day for 8 weeks lowered insulin by 4.35 mIU/L and total cholesterol by 5 mg/dL (0.13 mmol/L) but raised systolic blood pressure by 4.6 mmHg versus wheat bread. — Chinese high school adolescents, four classes randomized, 8 weeks (n = 123 (4 classes)) Evidence B source
  Net change vs wheat bread: SBP +4.6 mmHg (p = 0.010), insulin -4.35 mIU/L (p < 0.001), total cholesterol -5 mg/dL (-0.13 mmol/L) (p = 0.032), HDL-c -2.7 mg/dL (-0.07 mmol/L) (p = 0.010); urinary Na/K no difference
• In a randomized trial in 79 Chinese adults, potato-wheat steamed bread at lunch for 4 weeks cut weight by 1.3 lb (0.6 kg) and LDL cholesterol by 8.5 mg/dL (0.22 mmol/L) versus wheat bread. — 79 adults analyzed (49 potato-wheat bread, 30 wheat bread), mean age about 42, 4 weeks (n = 79) Evidence B source
  Weight -1.3 lb (95% CI -2.6 to -0.22; metric: -0.6 kg, -1.2 to -0.1), BMI -0.2 kg/m2 (95% CI -0.4 to -0.1), LDL-c -8.5 mg/dL (95% CI -19 to -0.39; metric: -0.22 mmol/L, -0.49 to -0.01)
• In the same 4-week adult trial, potato-wheat bread lowered LDL cholesterol by 8.5 mg/dL (0.22 mmol/L) and the urinary sodium to potassium ratio by 2.4 versus wheat bread. — 79 Chinese adults, lunch bread for 4 weeks (n = 79) Evidence B source
  LDL-c -8.5 mg/dL (95% CI -19 to -0.39, p = 0.035; metric: -0.22 mmol/L, -0.49 to -0.01); urinary Na/K -2.4 (95% CI -4.1 to -0.7, p = 0.007)

What people believe that the data does not support

• The EU allows the claim that replacing digestible starch with resistant starch in a meal reduces the blood glucose rise after it, but no claim names potato bread itself. — EU Register on nutrition and health claims, snapshot 2026-09-21 Evidence E source
  Authorized for resistant starch as a substance; conditions of use not in this layer

Who this works differently for

• In the same 8-week adolescent trial, potato bread lowered fasting glucose by 5.6 mg/dL (0.31 mmol/L) and insulin by 5.95 mIU/L in boys, while girls showed no glucose drop. — 123 students aged about 16, 58 control and 65 intervention (n = 123) Evidence B source
  Boys: glucose -5.6 mg/dL (95% CI -8.8 to -2.3; metric: -0.31 mmol/L, -0.49 to -0.13), insulin -5.95 mIU/L (95% CI -7.39 to -4.51); girls: glucose +2.7 mg/dL (95% CI -0.18 to 5.8, p = 0.069; metric: 0.15 mmol/L, -0.01 to 0.32)

The bottom line

The same school trial split its results by sex, which it had not set out to do. Boys on potato bread saw fasting glucose fall by 5.6 mg/dL (95% CI 2.3 to 8.8; metric: 0.31 mmol/L, 0.13 to 0.49) and insulin by 5.95 mIU/L. Girls showed no significant drop in glucose (+2.7 mg/dL (0.15 mmol/L), p = 0.069). In the adult trial the urinary sodium to potassium ratio fell by 2.4 against wheat bread, measured in a single morning urine sample. For a sandwich, a medium US slice weighs 1.2 oz (34 g) and carries about 90 calories, 16 g carbohydrate and 128 mg sodium, worked out from the 100 g values and not weighed as a portion. Toasting drives off water, so 3.5 oz (100 g) of toast has 292 calories against 266. The slice shrinks to 31 g and stays at about 90 calories. The FNDDS models that water loss and does not measure any change in the starch. Potato flour is sometimes talked up for resistant starch. In a test tube digestion model, replacing 15 percent of wheat flour with potato flour raised resistant starch from 5.2 to 11.3 percent and the calculated glycemic index from 95 to 87. We found no trial that checked this in people. The EU allows a claim that swapping digestible starch for resistant starch in a meal contributes to a smaller blood glucose rise after it. No claim names potato bread, and whether an ordinary loaf reaches the amount the rule requires is unknown. Every bread tested in these studies was based on wheat flour: the Chinese trials mixed potato flour into wheat bread, and the lab model replaced at most 15 percent of the wheat flour. Our cards do not say what flour goes into the US loaf, so the word potato is no sign that a loaf is free of wheat or gluten. We have no card on allergy, pregnancy or medicines for potato bread, so this page cannot tell you who should be careful with it.

Sources

1. ptbr-daily-r6-01 · food composition dataset
   Bread, potato (FNDDS 51127010): Energy 266 kcal, Carbohydrate by difference 47.07 g, Protein 12.5 g, Fiber total dietary 6.3 g, Total Sugars 9.38 g, Sodium 375 mg per 100 g
   USDA FNDDS 2021-2023, food code 51127010, FDC 2707642 · checked 2026-09-29
2. ptbr-daily-r6-02 · food portion dataset
   Bread, potato: 1 small or thin/very thin slice = 26 g; 1 medium or regular slice = 34 g; 1 large or thick slice = 43 g; Quantity not specified = 34 g
   USDA FNDDS 2021-2023, food code 51127010, FDC 2707642 · checked 2026-09-29
3. ptbr-daily-r6-09 · in vitro study
   Bread with no potato flour had 5.2% RS and an eGI of 95, while the bread with 15% potato flour had 11.3% RS and an eGI of 87.
   Int J Food Sci Technol, 2020 (Whitney and Simsek) · checked 2026-09-29
4. ptbr-daily-r6-03 · food composition dataset
   Bread, potato, toasted (FDC 2707643): Energy 292 kcal, Carbohydrate by difference 51.72 g, Sodium 412 mg per 100 g; 1 medium or regular slice = 31 g
   USDA FNDDS 2021-2023, FDC 2707643 and 2707642 · checked 2026-09-29
5. ptbr-daily-r6-04 · RCT
   Compared with the control group, the intervention group had significant net changes in systolic blood pressure (4.6 mmHg, p = 0.010), insulin (-4.35 mIU/L, p < 0.001), total cholesterol (-0.13 mmol/L, p = 0.032), and high-density lipoproteins cholesterol (-0.07 mmol/L, p = 0.010).
   Int J Environ Res Public Health, 2020 · checked 2026-09-29
6. ptbr-daily-r6-06 · RCT
   In total, 79 participants were analyzed in the study (30 in the control group and 49 in the intervention group). ... Compared with the control group, the net changes in weight and BMI for the intervention group after 4 weeks of bread intake were −0.6 kg (95% confidence interval [CI]: −1.2, −0.1; p = 0.016) and −0.2 kg/m2 (95% CI: −0.4, −0.1; p = 0.020), respectively.
   Front Nutr, 2022 · checked 2026-09-29
7. ptbr-daily-r6-07 · RCT
   a significant net change (mean between-group difference) of −0.22 mmol/L for LDL-c (95% CI: −0.49, −0.01; p = 0.035) was observed in the intervention group after 4 weeks of potato bread intake (Figure 2). ... Significant changes in the Na+/K+ ratio were observed of −2.4 (95% CI: −4.1, −0.7; p = 0.007) overall, −2.9 (95% CI: −5.6, −0.1; p = 0.039) among men, and −1.7 (95% CI: −4.0, 0.7; p = 0.162) among women (Table 3).
   Front Nutr, 2022 · checked 2026-09-29
8. ptbr-daily-r6-10 · authority decision
   POL-HC-6449 Resistant starch Replacing digestible starches with resistant starch in a meal contributes to a reduction in the blood glucose rise after that meal. Authorised
   EU Register on nutrition and health claims, claim POL-HC-6449, snapshot 2026-09-21 · checked 2026-09-29
9. ptbr-daily-r6-05 · RCT
   A total of 123 students were enrolled in the study (58 in the control group and 65 in the intervention group). ... Significant net changes of GLU and INS were identified in both sex subgroups: −0.31 mmol/L (95% CI: −0.49, −0.13; p = 0.001) and −5.95 mIU/L (95% CI: −7.39, −4.51; p < 0.001), respectively, for intervention boys, and 0.15 mmol/L (95% CI: −0.01, 0.32; p = 0.069) and 2.26 mIU/L (95% CI: −3.98, −0.55; p = 0.010), respectively, for intervention girls (Table 4).
   Int J Environ Res Public Health, 2020 · checked 2026-09-29