One serving against a day's fiber
The Dietary Reference Intakes set an Adequate Intake for total fiber of 25 g a day for women aged 19 to 50 and 38 g for men of the same ages. Measured against those, the 16 g in a 1 cup, without shell serving of sunflower seeds, plain, unsalted is 64% of the first and 42% of the second. US food labels use a single Daily Value of 28 g instead, which puts this serving at 57%.
Calorie for calorie, the figure is 1.9 g of fiber per 100 kcal (this serving is 838 kcal). Among the 14 seeds with USDA energy data here that is 5th, and 479th across all 957. The intakes above were derived from 14 g of fiber per 1,000 kcal, or 1.4 g per 100 kcal, so this food sits above the ratio a whole day of eating is meant to reach.
Getting all 25 g from sunflower seeds, plain, unsalted alone would take 2 servings, and 38 g would take 3. Most days reach the target through several different sources.
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