For example the nutrition facts for 100 grams of Black Eyed peas ( https://imgur.com/a/WDidCOb ) says 0.5 g fat, 21g carbs, 8 g protein and like 300 mg of potassium and sodium. All of this don’t even add up to 30%. What’s the other 70% of the weight?
Water in cooked foods. Fiber in dry foods.
Nutrient numbers are averages of multiple samples. Natural foods vary. Every lab seems to crank out slightly different numbers.
Numbers on packaging have a margin of error of ±20%