Spaghetti: a low glycaemic index, and two things the label will not tell you

Spaghetti is the refined starch that does not behave like one. In healthy adults it measured a glycaemic index of 44 against 63 for rice, and regular, whole wheat and high fibre versions came out at 33, 38 and 41. In that trial, on 14 young adults, the three types did not differ from each other in glucose, insulin or appetite, so the fibre on the box made no difference there. Over a longer run, or in other people, nobody has measured it. The reason the index is low is mechanical. Spaghetti leaves the stomach slowly, and in eight inpatients with diabetes the same 40 g of carbohydrate gave a glucose area of 284 as spaghetti against 607 as mashed potato. One warning before you read on. The weight figure here, 0.63 kg across 32 trial comparisons, belongs to a whole low glycaemic index way of eating rather than to pasta on its own, because no trial tested pasta by itself. Read the table that follows with care. It is matched to the word rather than to the food. It carries spaghetti squash, which is a vegetable, along with spinach, canned and protein fortified products, so nothing in it describes plain cooked pasta.

The numbers, per 100 g

What your body absorbs

• In 8 inpatients with type 2 diabetes, 40 g of carbohydrate as spaghetti gave a glucose area of 284 against 607 as mashed potato, and the slower gastric emptying behind that is what keeps the glycaemic index of spaghetti low in them. — 8 inpatients with non-insulin-dependent diabetes, 40 g of carbohydrate as spaghetti or mashed potato with paracetamol as the gastric emptying marker, 4 hour observation (n = 8) Evidence B source
  Glucose area 284 ± 54 vs 607 ± 108 mmol/l per 240 min for spaghetti against potato, P = 0.02, with an emptying index of 0.4 ± 0.1 vs 2.1 ± 0.3, P = 0.001
• In 19 healthy adults, a week each on tomato juice, spaghetti sauce and tomato oleoresin raised serum lycopene and lowered a marker of lipid oxidation. — 19 healthy adults, one week each on tomato juice, spaghetti sauce and tomato oleoresin, randomised crossover (n = 19) Evidence B source
  Significant rise in serum lycopene and fall in thiobarbituric acid reactive substances; protein and DNA oxidation fell without reaching significance

What cooking and storage change

• Adding 10% of one barley beta-glucan concentrate to semolina spaghetti cut its glycaemic index from 64 to 29 in nine healthy adults, while another concentrate at the same dose changed nothing. — 9 healthy adults, spaghetti samples with 0 to 10% beta-glucan from two different barley concentrates, 50 g available carbohydrate per portion (n = 9) Evidence B source
  Glycaemic index 29 for 10% Barley Balance against 64 for the control, a 54% drop, P ≤ 0.02; the Glucagel concentrate gave values like the control
• Spaghetti gave a glycaemic index of 44 against 63 for rice in healthy adults, and adding tomato sauce with extra virgin olive oil or pesto did not change the glucose response of either dish. — healthy young adults eating spaghetti and rice plain, then with tomato sauce and extra virgin olive oil, then with pesto Evidence B source
  Glycaemic index 44 ± 7 for spaghetti vs 63 ± 3 for rice, p = 0.003; glucose area 82.1 vs 124.2 mmol per min per L, p = 0.016; no significant change from either condiment

What it does to your health

• Across 32 trial comparisons in 2448 adults, pasta eaten inside a low glycaemic index diet reduced body weight by 0.63 kg against higher glycaemic index diets. — 2448 adults in randomised trials of at least 3 weeks, pasta as part of low glycaemic index dietary patterns (n = 2448) Evidence A source
  Body weight -0.63 kg, 95% CI -0.84 to -0.42; BMI -0.26 kg/m2, 95% CI -0.36 to -0.16; no effect on waist or body fat; GRADE moderate for weight and BMI
• Regular, whole wheat and high fibre spaghetti all measured a low glycaemic index of 33, 38 and 41 in 14 healthy adults, and in that trial the three types did not differ from each other in glucose, insulin or appetite. — 14 healthy adults aged 25 ± 1 years, isoglucidic test meals of 50 g available carbohydrate against a 50 g glucose reference (n = 14) Evidence B source
  Glycaemic index 33 regular, 38 whole wheat, 41 high soluble fibre, all in the low band; no difference between types in glucose, insulin or appetite

Safety, limits and interactions

• Spaghetti was 8% of total dietary cadmium intake in the United States, second only to lettuce at 14%, in an analysis of 12523 people. — 12523 Americans aged 2 and over in NHANES 2007 to 2012, two days of 24 hour recalls matched to the FDA Total Diet Study (n = 12523) Evidence C source
  Spaghetti 8% of total cadmium intake and lettuce 14%. Cadmium from the whole diet averaged 4.63 µg a day across the sample, which on a weekly footing is about 22% of the tolerable weekly intake of 2.5 µg per kg body weight
• In a school canteen outbreak that made 101 of 140 people ill, spaghetti carbonara carried an adjusted odds ratio of 8.4 for Salmonella enteritidis infection, on a confidence interval running from 1.4 to 51.8. — 140 of 185 people exposed to school canteen menus, eating a dish whose sauce was made with raw egg, historic cohort study with stool samples from 30 cases and 8 food handlers (n = 140) Evidence C source
  Adjusted OR 8.4, 95% CI 1.4 to 51.8; attack rate 72.1%, with 12.9% of cases hospitalised

What is still unknown

• In a secondary analysis of three randomised trials, the 120 minute glucose area for pure glucose showed no association with the one for pastas, and that inconsistency tracked BMI and fat mass index at P < 0.01. — secondary analysis of three randomised controlled trials in Asian populations, glucose and carbohydrate foods including semolina and wholegrain penne and spaghetti Evidence B source
  Positive correlations between glucose and simple sugars and rice varieties, but no association between the 120 minute glucose area for pure glucose and for pastas; inconsistency correlated with BMI and fat mass index, P < 0.01

The bottom line

What you put on top of it did not change the glucose response, in the one trial that tested that question. Healthy adults ate spaghetti plain, then with tomato sauce and extra virgin olive oil, then with pesto, and neither topping moved the glucose curve of the meal. That is what was measured, and it is about blood sugar and nothing else. Two of the friendlier findings on this page are about something other than a plate of pasta, and that matters if you are deciding what to buy. The lycopene result belongs to the sauce. Nineteen adults spent a week each on tomato juice, spaghetti sauce and tomato oleoresin, serum lycopene rose, and a marker of fat oxidation fell. That is a finding about tomatoes. The spaghetti whose glycaemic index dropped from 64 to 29 had 10 percent of a barley beta-glucan concentrate mixed into the semolina, and a second concentrate at the very same dose did nothing. You cannot reproduce that with a normal packet. Two safety findings sit under this page and both are worth stating plainly. The first is cadmium. In an analysis of 12523 Americans, cadmium coming in from the whole diet averaged 4.63 µg a day, and spaghetti was 8 percent of that total, second only to lettuce at 14 percent. Put on the same weekly footing, that whole diet figure works out at about 22 percent of the tolerable weekly intake of 2.5 µg per kg of body weight. So the number describes everything those people ate, and pasta is one slice of it. Cadmium arrives with the wheat, so no cooking method touches it. The second finding is about handling. In one school canteen 101 of 140 people fell ill and 12.9 percent of the cases went to hospital, and spaghetti carbonara carried an adjusted odds ratio of 8.4 for Salmonella enteritidis. The investigators named the dish and took samples from eight food handlers. The thing that carried the bacteria was the raw egg in the sauce, not the pasta, and the authors closed on the danger of using inadequately cooked eggs and asked for pasteurised egg products to be used more widely. So read that as a warning about dishes built on raw or barely cooked egg, and about how food is kept and handled. The odds ratio is a loose one as well, 8.4 on a confidence interval that runs from 1.4 all the way to 51.8. Now the gaps, because they are wide and nobody writes them down. We hold no study of spaghetti in pregnancy. Not one. The layer we search for interactions with medicines is organised by nutrient, so for a food it comes back empty by construction, which is a fact about our tools and not evidence that pasta interacts with nothing. If you take a medicine that turns on what you eat, that question belongs to the person who prescribed it. We also have no measured spread for the composition of pasta itself, and no retention factors for it, so how far one box sits from another, and what boiling takes out, stay open here. Neither the American nor the European register of health claims carries anything naming pasta. And one analysis found that a person whose blood sugar answers loudly to pure glucose does not necessarily answer the same way to a plate of pasta, with the mismatch growing as body fat grew. An index measured on 14 young adults describes the food. It does not predict you.

Sources

1. spag-r2-04 · randomised trial in type 2 diabetes
   This study shows that the ingestion of spaghetti was associated with a slower gastrointestinal accessibility of the carbohydrates, which accounts for the low glycaemic index of spaghetti in NIDDM subjects.
   Eur J Clin Nutr, 1994 · checked 2026-09-23
2. spag-r2-06 · randomised crossover trial in healthy adults
   Dietary supplementation of lycopene resulted in a significant increase in serum lycopene level and diminished amounts of serum thiobarbituric acid-reactive substances.
   Nutr Cancer, 1998 · checked 2026-09-23
3. spag-r2-03 · randomised crossover trial in healthy adults
   In particular, the GI of 10% BB spaghetti was 54% lower (P ≤0.02; GI = 29) than that of the control (GI = 64).
   Nutrition, 2011 · checked 2026-09-23
4. spag-r2-05 · randomised crossover trial in healthy adults
   The GI of R (63 ± 3) was statistically higher than that of S (44 ± 7) (p = 0.003).
   Nutr Metab Cardiovasc Dis, 2021 · checked 2026-09-23
5. spag-r2-01 · meta-analysis of randomised controlled trials in adults
   Pasta in the context of low-GI dietary patterns significantly reduced body weight (MD=-0.63 kg; 95% CI -0.84 to -0.42 kg) and BMI (MD=-0.26 kg/m2; 95% CI -0.36 to -0.16 kg/m2) compared with higher-GI dietary patterns.
   BMJ Open, 2018 · checked 2026-09-23
6. spag-r2-02 · randomised crossover trial in healthy adults
   All three spaghetti types (regular, whole wheat, and high soluble fiber-low carbohydrates) provided low GI values (33, 38, and 41, respectively, on glucose scale) and lower peak glucose values compared to glucose or white bread.
   Int J Environ Res Public Health, 2022 · checked 2026-09-23
7. spag-r2-07 · cross-sectional analysis of NHANES
   The foods that contributed most to total Cd intake were lettuce (14%), spaghetti (8%), bread (7%), and potatoes (6%).
   Nutrients, 2018 · checked 2026-09-23
8. spag-r2-08 · outbreak cohort investigation
   The multivariate analysis showed that, while the spaghetti maintained its association (ORa = 8.4; 95% CI 1.4-51.8), the meat balls registered a reduction in risk (ORa = 1.8; 95% CI 0.4-7.5).
   Enferm Infecc Microbiol Clin, 2000 · checked 2026-09-23
9. spag-r2-09 · secondary analysis of randomised trials
   However, there were a lack of associations between iAUC120 min for glucose with pastas (semolina and wholegrain penne, spaghetti) and mee pok noodles.
   Eur J Clin Nutr, 2024 · checked 2026-09-23