Glycemic Index of Pasta: Lower Than You Think, and the Plate Decides
White spaghetti tests around GI 49, lower than wholemeal bread. The published values by type, why the al dente rule is shakier than everyone claims, and the load of a real plate.
Pasta is the food that breaks people’s mental model of carbohydrates.
Short answer: boiled white spaghetti has a published GI of about 49 — lower than wholemeal bread, lower than most breakfast cereals, lower than a boiled potato. Published values do run lower for briefly boiled pasta (~38) and higher for pasta boiled 20 minutes (~58–61), though as the caveat below explains, that gradient is shakier than it looks. And the plate size decides the rest.
The numbers
| Pasta (boiled) | Published GI |
|---|---|
| Spaghetti, white, boiled 5 min | ~38 (mean of 4 studies) |
| Spaghetti, white, boiled 10–15 min | ~49 (mean of 6 studies) |
| Spaghetti, white, boiled 20 min | ~58–61 |
| Spaghetti, wholemeal | ~42–48 |
| Fresh egg pasta | ~40–55 (fresh entries cluster 45–51) |
| Maize/rice gluten-free pasta | ~46–92; most fall 50–78 |
Figures from the University of Sydney GI database and the international GI tables (Foster-Powell 2002, Atkinson 2008/2021). Values are means across studies; individual products vary widely.
Two things stand out. Wholemeal is barely lower — a few points, not a category change. And gluten-free pasta is usually higher and far less predictable, because maize and rice starch gelatinise more freely without the wheat protein holding them back. Brown rice pasta has tested as high as 92.
Why pasta behaves oddly
Extruded pasta is dense. The dough is forced through a die under pressure, which packs starch granules inside a tight protein network. Boiling gelatinises some of that starch, but the matrix keeps enzymes from reaching all of it — so digestion is slower than the same flour baked into bread.
The al dente claim needs a caveat
Look at the table and the story writes itself: boil longer, get a higher number. It’s the most repeated piece of pasta advice on the internet, and the evidence for it is weaker than the table implies.
Those rows come from different studies, in different labs, with different subjects and brands. When researchers tested cooking time inside a single experiment, they didn’t find the effect. Wolever and colleagues (1986) reported that spaghetti’s glycemic index was “not significantly affected by cooking for 5 or 15 min”. Bornet and colleagues (1990) tested 11, 16.5 and 22 minutes and found “no significant differences between cooking times” — their 22-minute result was the lowest of the three.
So the honest version: al dente pasta plausibly sits at the lower end, but the gradient in the tables is partly an artefact of comparing across studies. The University of Sydney still advises against overcooking, and Diabetes Canada explicitly recommends cooking pasta al dente. It’s sensible advice with a thinner evidence base than its confidence suggests, and we’d rather say that than print a tidy causal claim.
Cooling is better evidenced. Cooked-then-chilled pasta forms resistant starch, and a 2026 randomised crossover in 32 adults with type 1 diabetes found chilled-and-reheated pasta produced substantially lower glucose responses than freshly cooked. The same chemistry applies to rice and potatoes. Pasta salad is quietly the lowest-GI way to eat pasta.
The load of an actual plate
Here’s where the low GI stops being reassuring. Pasta is carb-dense, and restaurant portions are large:
| Plate (cooked) | Available carb | GI | GL |
|---|---|---|---|
| 100 g, side portion | ~27 g | 49 | ~13 |
| 180 g, standard serving | ~48 g | 49 | ~24 |
| 180 g, boiled 5 min | ~48 g | 38 | ~18 |
| 300 g, restaurant plate | ~80 g | 49 | ~39 |
Cooked pasta runs about 27 g of available carbohydrate per 100 g, which is why the 180 g serving used in the GI tables carries 48 g and computes to a published load of 24.
A low-GI food at a high portion is still a high-load meal. That’s the whole GI-versus-GL distinction in one table: the index describes the pasta, the load describes your dinner. Run your own numbers in the glycemic load calculator.
What the number doesn’t say
These are published food values measured in isolation. Your plate isn’t isolated: olive oil, cheese, meat and vegetables all slow gastric emptying, and a bolognese behaves differently from plain pasta with the same carbohydrate count. Mixed meals are consistently harder to predict than single foods, which is why nobody honest promises a spike forecast.
In 3sense Food, a plate of spaghetti carries its GI as published and its load calculated from the grams you actually logged — so 180 g al dente and a 300 g heap stop arriving as the same entry in your diary.
Quick answers.
What is the glycemic index of pasta?+
Boiled white spaghetti has a published GI around 49, the mean of six studies, which is lower than most breads made from the same wheat. Wholemeal versions test slightly lower again, in the mid-40s.
Does cooking pasta al dente lower its glycemic index?+
Probably, but less clearly than the tables suggest. Published means fall as cooking time shortens, yet the two studies that varied cooking time within a single experiment found no significant difference. The University of Sydney and Diabetes Canada both still advise cooking pasta al dente.
Is wholemeal pasta much lower GI than white?+
Only slightly. The published gap between white and wholemeal spaghetti is a handful of points, far smaller than the effect of portion size.
What is the glycemic load of a plate of pasta?+
A 180 g cooked serving holds roughly 48 g of available carbohydrate; at GI 49 that computes to a glycemic load around 24. A 300 g restaurant plate lands near 39.