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 6.3 g in a 1 large slice serving of pie, blueberry is 25% of the first and 17% of the second. US food labels use a single Daily Value of 28 g instead, which puts this serving at 23%.
Calorie for calorie, the figure is 0.8 g of fiber per 100 kcal (this serving is 750 kcal). Among the 110 packaged with USDA energy data here that is 52nd, and 794th 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 below the ratio a whole day of eating is meant to reach.
Getting all 25 g from pie, blueberry alone would take 4 servings, and 38 g would take 7. Most days reach the target through several different sources.
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