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 4.5 g in a 1 medium serving of sweet potato, boiled, fat added is 18% of the first and 12% of the second. US food labels use a single Daily Value of 28 g instead, which puts this serving at 16%.
Calorie for calorie, the figure is 2.6 g of fiber per 100 kcal (this serving is 173 kcal). Among the 121 fruits with USDA energy data here that is 65th, and 378th 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 sweet potato, boiled, fat added alone would take 6 servings, and 38 g would take 9. Most days reach the target through several different sources.
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