Hi i come from singapore. Singapore has very few low carb foods and i just went to the supermarket to find some products that i can eat.

Is it true that no matter what i must not exceed 20g of carbo?
I found out that some items has about 4-5g of carbo. Can i eat that?

I have only found some foods that i can eat.
eggs
cheese
ham
corned beef
tuna
salmon

When i look on those on the shelf food like fishball, meatball, those processed food that needs to be fried, i found out that there are some carbo in them(4-5g of carbo). Can i eat them?