Water chestnuts are a crunchy root type vegetable used very often in asian cooking. I love water chestnuts, and consider them a special treat. Even though they're called chestnuts, they're not nuts at all. They're only called water chestnuts because they look similar.
These are perfect for stir fry dishes. They're small - just about bite sized. They are crunchy, mild in flavor and a bit sweet. If the rest of your dish gets a bit mushy, it's wonderful to have that crisp counterpart to add to the texture.
You can dice them up into smaller pieces and add them into a salad, even into meatloaf and burgers.
They don't have any fat at all. For a half cup, you get about 9g of carbs. While this is high for someone just starting a diet, if you're further into your diet plans, it's not bad at all. Plus, if you're sprinkling slivers of water chestnut over your salad for some crunch, I doubt you get anywhere near a half cup of them. You probably get 1 or 2 chestnuts in there - which is pretty much zero carbs, but with a great flavor.
You're not getting much nutrition in here, so don't rely on water chestnuts to keep you healthy. You only get 2% of your iron and 2% of your calcium for a full half cup. That's pretty much nothing, considering how much other sources provide to you.
A classic, easy appetizer restaurant with water chestnuts is to wrap each water chestnut with a small piece of bacon. Hold it closed with a toothpick. Bake a sheet of these in a 350F oven for a half hour. You can serve this with a number of dipping sauce options, or just present them plain. Bacon is zero carb, so the only carbs here are those in the water chestnuts.
If you want to marinade the water chestnut appetizers for more flavor, after that first cooking, pour a mixture of low carb ketchup and Splenda or soy sauce over them. Then cook for another half hour or so at 350F. If you enjoy more of a brown sugar flavor, go for a low carb maple syrup. It ends up giving the same sort of rich flavor.