Starch Portion Equivalence Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/10/2026
A starch portion varies by type: 75-125 g for bread, 180-300 g for potatoes, 60-100 g for dried raw legumes, 45-75 g for raw cereals, pasta, or rice. 100 g of bread equals about 0.8 to 1.3 portions.
Explanation
Unlike a fiber-rich food group whose PNNS reference portion stays relatively stable regardless of the specific item (as our fiber intake calculator illustrates by tracking a single daily target), starchy foods show very different reference portions depending on the exact type eaten, due to widely varying energy density and water content: a bread portion (75-125 g) weighs much less than a potato portion (180-300 g, richer in water), itself different from a portion of dried legumes or raw cereals/pasta/rice (45-100 g, since cooking then multiplies their weight by 2 to 3). France's national nutrition program (PNNS) recommends eating starches at every meal according to appetite, which in practice amounts to 3 to 6 portions a day across all categories combined. This benchmark concerns the amount and frequency of eating starches as a food group, independent of their overall caloric contribution already covered by our macronutrient calories calculator. Favoring whole-grain over refined versions within this group is also recommended, at least one whole-grain starch per day, for their extra fiber content.
Example: 100 g of bread
Inputs
Quantity consumed: 100 g. Starch type: bread.
Calculation
Minimum = 100 ÷ 125 = 0.8 portion. Maximum = 100 ÷ 75 ≈ 1.33 portion.
Result
100 g of bread equals about 0.8 to 1.3 portions.
Frequently asked questions
Why does the starch portion vary so much by type?
Because energy density and water content differ greatly from one starch to another: potatoes, rich in water, need a much higher weight to provide a carbohydrate amount comparable to a bread portion, which is drier and denser. Cereals, pasta, and dried legumes, meanwhile, are weighed raw, before cooking multiplies their weight by 2 to 3.
Why is the weight of legumes and cereals given raw rather than cooked?
Because raw weight remains the most stable and easiest reference to measure before cooking, which makes these foods swell by absorbing water in proportions that vary by cooking method and time. Generally count a factor of 2.5 to 3 for pasta and rice (100 g raw yields about 250-300 g cooked), and a factor of 2 for dried legumes.
Should certain starches be favored over others?
The PNNS recommends varying starches and favoring whole-grain versions (whole-grain bread, pasta, rice) over refined ones at least once a day, for their extra fiber, vitamin, and mineral content, partly lost when cereals are refined.