Melba toast: light per piece, dense per gram

Drying bread into thin crisp slices does not turn it into a gentler carbohydrate. In a randomized trial in 12 healthy adults, white bread toasted into a rusk had a glycemic index of 99 against 115 for the same bread eaten fresh, a gap that did not reach significance. That small 1988 study is the only direct comparison of fresh and dried versions of one bread we found, and melba toast is thinner and drier than the rusk it tested. In 17 people with type 2 diabetes, 2.1 oz (60 g) of hard toasted bread gave no lower glucose response than 3.2 oz (90 g) of white bread carrying the same 50 g of carbohydrate. Gram for gram, melba toast holds more energy than bread. The US dietary survey database lists 390 calories per 3.5 oz (100 g), against 267 calories for white bread and 293 calories for toasted white bread. The lightness is in the piece. One slice weighs 5 g, which works out at about 19.5 calories and 30 mg sodium, a figure calculated from the 100 g values rather than measured on a single slice.

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

How much is actually in it

• Bread crust is a major dietary source of melanoidins, brown Maillard products of baking. Estimated intakes are 1.8 to 15.0 g a day from bread and 3.2 to 8.5 g a day from dry biscuits. — melanoidin content measured in coffee brews, bread and dry biscuits, intake estimated for the general population Evidence D source
  Estimated melanoidin intake 1.8-15.0 g/day from bread, 3.2-8.5 g/day from dry biscuits, about 10 g/day from all sources
• Per 100 g, melba toast in the US dietary survey database carries 390 calories, 76.6 g carbohydrate, 12.1 g protein, 6.3 g fiber and 598 mg sodium. — Melba toast as coded in FNDDS 2021-2023 Evidence E source
  390 calories, 76.6 g carbohydrate, 12.1 g protein, 6.3 g fiber, 598 mg sodium per 3.5 oz (100 g)

What a real portion looks like

• One melba toast weighs 5 g in the US dietary survey database, so a piece carries about 19.5 calories and 30 mg sodium. An unspecified amount is 18 g. — household measures for Melba toast in FNDDS 2021-2023 (n = 5 household measures) Evidence E source
  1 piece 5 g, 19.5 calories, 29.9 mg sodium; quantity not specified 18 g, 70 calories
• US labeling law names melba toast explicitly and sets its reference amount at 15 g, about three pieces, which is the basis for the serving on a US label. — melba toast sold with US Nutrition Facts labels Evidence E source
  Reference amount 15 g

What your body absorbs

• In a randomized study in 40 healthy adults, adding cheddar cheese to toast cut the glycemic index of the meal to 35, a low-GI value. — 40 healthy adults (11 men, 29 women), staff and students in Oxford, UK (n = 40) Evidence B source
  GI of toast with cheddar 35; toppings as a group lowered GI consistently, differences among toppings for toast not significant (P=0.39)

Safety, limits and interactions

• Laboratory-made rusks, sliced bread dried at 150 C after baking, contained 71.94 ug/kg acrylamide against 59.07 ug/kg in the bread before drying. — yeast-dough bread and rusks made from it in the laboratory, without added oat fiber (blank samples) Evidence D source
  Acrylamide 59.07 ug/kg in bread vs 71.94 ug/kg in rusks; adding 15% oat fiber cut it by about 60% in rusks

What people believe that the data does not support

• Melba toast is not a low-calorie form of bread by weight: at 390 calories per 3.5 oz (100 g) it is denser than white bread (267 calories) or toasted white bread (293 calories), because drying removes water. — Melba toast, white bread and toasted white bread as coded in FNDDS 2021-2023 Evidence E source
  390 vs 267 vs 293 calories per 3.5 oz (100 g)

Who this works differently for

• In 17 people with type 2 diabetes, 2.1 oz (60 g) of hard toasted bread raised blood glucose about as much as 3.2 oz (90 g) of white bread. Only potato dumplings gave a lower response. — 17 patients with type 2 diabetes (11 men, 6 women), each test food giving 50 g available carbohydrate, glucose followed for 180 min (n = 17) Evidence B source
  No lower glucose response for hard toasted bread vs white bread; potato dumplings lower at 90, 120 and 150 min
• In a 12-week randomized trial in 156 adults at risk of type 2 diabetes, a high-GI Mediterranean diet whose starches included rusks raised 8-hour blood glucose by up to 37% in women but not in men, compared with a low-GI diet. — 156 adults (82 women, 74 men) with at least two traits of the metabolic syndrome in Italy, Sweden and the United States, 12 weeks (n = 156) Evidence B source
  8-h average plasma glucose 23% higher on day 1 and 37% higher after 12 weeks in women on the high-GI diet (p < 0.05); no significant difference in men

What is still unknown

• In a randomized trial in 12 healthy adults, toasting white bread into a rusk did not meaningfully change its glycemic index: 99 for the rusk against 115 for the same white bread, a difference that was not significant. — 12 healthy volunteers (8 women, 4 men, mean age 24), each meal giving 35 g carbohydrate, tested in random order on four consecutive days (n = 12) Evidence B source
  Glycemic index 115 (white bread) vs 99 (toasted rusk from the same bread) vs 87 (bran-enriched rusk), not significant

The bottom line

In the studies we found, what went on top moved the glycemic index more than the drying did. In a randomized study in 40 healthy adults in Oxford, adding cheddar cheese to ordinary toast brought the glycemic index of the meal down to 35, a low value, and that toast was regular toasted bread. In a 12 week trial in 156 adults with at least two traits of the metabolic syndrome, a high glycemic index Mediterranean diet raised 8 hour blood glucose by 37 percent in women compared with a low index diet, with no significant difference in men. Rusks were one of five starches on that diet, so the result belongs to the diet as a whole. Per 100 g the survey database gives 12.1 g protein, 6.3 g fiber and 598 mg sodium. US labeling law names melba toast and sets its label serving at 15 g, roughly three slices, which is a rule for the label and says nothing about how much you should eat. On safety we have one laboratory finding. Rusks made from yeast bread and dried at 150 C held 71.94 micrograms of acrylamide per kilogram against 59.07 in the bread before drying, in one recipe baked in a lab rather than a commercial melba toast. Apart from safety, bread crust is a major source of melanoidins, the brown products of baking, with estimated intakes of 1.8 to 15.0 g a day from bread and 3.2 to 8.5 g from dry biscuits, an estimate from lab measurements that never tested melba toast itself. We found no card on melba toast and wheat allergy, children, pregnancy or medicines, so this page has nothing to say about them.

Sources

1. mlb-r6-06 · laboratory analysis
   Major dietary sources of melanoidins are coffee and bread crust. ... For bread and dry biscuits an intake in the ranges of 1.8-15.0 and 3.2-8.5 g per day has been calculated.
   Food Funct, 2011 · checked 2026-09-29
2. mlb-r6-07 · reference dataset
   Melba toast - FNDDS 51187000 - Energy 390 KCAL - Carbohydrate 76.6 G - Protein 12.1 G - Fiber 6.3 G - Sodium 598 MG per 100 g
   USDA FNDDS 2021-2023, Melba toast, food code 51187000 · checked 2026-09-29
3. mlb-r6-09 · reference dataset
   Melba toast - FNDDS 51187000 - 1 cracker 5 g - 1 melba toast 5 g - 1 crostini 5 g - 1 cup, NFS 30 g - Quantity not specified 18 g
   USDA FNDDS 2021-2023, Melba toast, food code 51187000 · checked 2026-09-29
4. mlb-r6-10 · regulation
   Crackers that are usually not used as snack, melba toast, hard bread sticks, ice cream cones ... 15 g
   21 CFR 101.12, Table 2, Reference amounts customarily consumed · checked 2026-09-29
5. mlb-r6-03 · randomized repeated measures trial
   In particular, the addition of cheddar cheese to potato, pasta and toast reduced the GI of the test meal to a value that is considered to be low-GI (39, 27 and 35, respectively).
   Eur J Clin Nutr, 2006 · checked 2026-09-29
6. mlb-r6-05 · laboratory study
   The highest acrylamide content, both in baked goods and in rusks, amounting to 59.07 µg kg−1 and 71.94 µg kg−1, respectively, was found in the blank samples, i.e., without oat fiber.
   Molecules, 2024 · checked 2026-09-29
7. mlb-r6-08 · reference dataset
   Melba toast (FNDDS 51187000, fdc 2707702) Energy 390 KCAL | Bread, white (fdc 2707598) Energy 267 KCAL | Bread, white, toasted (fdc 2707599) Energy 293 KCAL, per 100 g
   USDA FNDDS 2021-2023, Melba toast, food code 51187000 · checked 2026-09-29
8. mlb-r6-02 · randomized crossover trial
   an equivalent amount of carbohydrate provided by one (n 8) or two (n 9) of three other different test foods (g): pizza 85, potato dumplings 165, hard toasted bread 60 ... Plasma glucose response, measured for 180 min, was significantly lower after the potato dumplings than after white bread at 90 (P < 0.05), 120 (P < 0.01), and 150 (P < 0.05) min.
   Br J Nutr, 2001 · checked 2026-09-29
9. mlb-r6-04 · randomized controlled trial
   jasmine rice, potato, couscous, wholegrain bread, and rusks ... In women, the high-GI induced significantly higher (23%, p < 0.05) 8-h average plasma glucose concentrations in comparison to the low-GI diet already on the first day of the intervention; the difference increased up to 37% (p < 0.05) after 12 weeks of diet. Conversely, there were no significant differences between the two diets in men.
   Clin Nutr, 2023 · checked 2026-09-29
10. mlb-r6-01 · randomized crossover trial
    The mean results of the glycemic indexes were: WB = 115 +/- 17%; FT = 99 +/- 21%; BFT = 87 +/- 21% (NS) ... Neither the toasting process nor the presence of wheat bran had any major effect upon hyperglycemia and insulin secretion in the healthy subjects studied.
    Diabete Metab, 1988 · checked 2026-09-29