Not much...
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Bean sprouts are known for containing very low amounts of carbs: just 5 grams per serving, with 2 of those coming from fiber - which doesn't count as carbs.
Fiber doesn't count as carbs because it isn't absorbed into the bloodstream and so it gets eliminated by the GI tract along with the rest of whatever else the body doesn't want to absorb.
An entire cup of bean sprouts contains 4 grams of carbohydrate then which may seem like a lot for a vegatable that is mostly water. Those carbs are considered sugars too.
But sugars in non-starchy vegetables (like spinach for example) are not the same as sugars you'd find in fudge candy. You'd notice the difference between eating a tiny piece of fudge and a cup of bean sprouts. You'd feel worse with the fudge because the sugars from it affect your insulin. From the sprouts you wouldn't get much of a rise if any of your insulin level.
Bean sprouts are a very good choice if you are looking to increase your nutrient intake through your diet. A cup or two gives you lots of nutrition with very few carbs and negligeable sugar content.
Eat and enjoy.
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