Pasta and Diabetes: Carbs, Glycemic Index and Portions
A cup of cooked spaghetti has about 38 g of carbohydrate (36 g net). Glycemic index: low (45 to 55). Yes, in measured portions. Pasta is a carbohydrate food, and a restaurant bowl is often two or three servings.
Pasta has a lower glycemic index than many people expect, especially when cooked al dente, because it is dense and digests slowly. That said, a restaurant plate is a lot of carbohydrate, so the portion is what decides how much it moves your glucose.
Cooking it a little firm, filling the rest of the plate with vegetables and adding protein makes a pasta night easier to fit in. Whole-wheat and bean-based pastas have more fiber, with a different taste and texture.
Carbs in pasta by portion
| Portion | Grams | Carbs (g) | Fiber (g) | Net carbs (g) | Protein (g) |
|---|---|---|---|---|---|
| cup spaghetti not packed | 124 | 38 | 2.2 | 36 | 7.2 |
| cup spaghetti packed | 151 | 47 | 2.7 | 44 | 8.8 |
| cup elbows not packed | 120 | 37 | 2.2 | 35 | 7 |
| 100 g (for comparing foods) | 100 | 31 | 1.8 | 29 | 5.8 |
Source: USDA FoodData Central, FDC ID 169737 (Pasta, cooked). Net carbs here means carbohydrate minus fiber. “Net carbs” is not an FDA-defined term, so total carbs are shown too. Values are estimates for a typical item; brands, ripeness and size vary.
Glycemic index and glycemic load
GI ranks how fast a food raises blood glucose compared with pure glucose (100). Low is 55 or less, medium 56 to 69, high 70 or more. Spaghetti, penne and other shapes from several brands and countries were tested. Glycemic load multiplies the index by the available carbohydrate in a portion (carbs minus fiber), so it reflects how much you actually eat: low is 10 or less, medium 11 to 19, high 20 or more.
Which published values we used (5)
| Entry | Food as listed | GI |
|---|---|---|
| Suppl. Table 1, #1467 | Spaghetti, white (Unico, Canada) | 45 |
| Suppl. Table 1, #1469 | Spaghetti, white (Unico, Canada) | 48 |
| Suppl. Table 1, #1472 | Spaghetti n°12 (De Cecco, Italy) | 50 |
| Suppl. Table 2, #3321 | Spaghetti, white | 50 |
| Suppl. Table 2, #3322 | Spaghetti, durum wheat, boiled in water | 55 |
Atkinson FS et al. International tables of glycemic index and glycemic load values 2021. Am J Clin Nutr 2021;114(5):1625-1632. Glucose reference (glucose = 100); values from studies that used white bread were converted by the authors. Where studies differ we show the range, not an average.
Glycemic index is only one piece of the picture. The same food can give a different response depending on ripeness, cooking, what you eat it with and your own body, so your meter or CGM is the best guide.
How pasta fit the plate method
Pasta count toward the carbohydrate quarter of the plate in the plate method, along with grains, starchy vegetables, fruit and milk. The CDC describes the plate method as half non-starchy vegetables, a quarter protein and a quarter carbohydrate foods. See the diabetic meal plan guide for how it works, or drop pasta onto a meal in the meal planner to watch the plate fill.
Portion ideas and pairings
- A half to one cup cooked is a typical portion.
- Share an entrée, or box half before you start eating.
- Stir in plenty of vegetables to stretch the dish.
Pairs well with: a big salad or roasted vegetables, chicken, shrimp or white beans, tomato sauce with no added sugar.
Related foods
Sweet potato
cup, cubes: 27 g carbs
Potato
Potato medium: 37 g carbs
White rice, cooked
cup: 45 g carbs
Quinoa, cooked
cup: 39 g carbs
See all foods and the low glycemic foods list
Frequently asked questions
Does al dente pasta really matter?
In studies, firmer pasta tends to give a lower glucose response than soft, overcooked pasta. Portion size still matters most.
How many carbs are in a cup of cooked spaghetti?
About 38 g of carbohydrate, of which about 2.2 g is fiber, so roughly 36 g net carbs. Values are from USDA FoodData Central for 124 g and are estimates; brands and sizes vary.
Information only, not medical advice. Your care team may set different targets for you, and only a lab test ordered by a clinician can diagnose diabetes or prediabetes. See our medical disclaimer.
Sources
- USDA FoodData Central: Pasta, cooked (FDC ID 169737)
- Atkinson FS et al. International tables of glycemic index and glycemic load values 2021. Am J Clin Nutr 2021;114(5):1625-1632
- CDC: Diabetes Meal Planning (plate method and carbohydrate counting)
- ADA Standards of Care in Diabetes—2026, Section 5: Facilitating Positive Health Behaviors
Last reviewed: by the Diabetes Blogs editorial team. Information only, not medical advice.
