Tofu comes from the soybean, just as cheese comes from milk. In 100g of Tofu there are 4g of fat and less than 1g of carbohydrate. So it is more fat than carb, but it is barely either. So Tofu can be eaten with cheese as a fat meal or with vegetables and beans as a carb meal.
We don’t normally talk about protein, as we are more interested in fats and carbs. However, Tofu is an excellent source of vegetarian protein. In 100g of Tofu there are 8g of protein. It is a great source of calcium and has all eight essential amino acids. The rest of the 100g, not accounted for, is water.
Please do also see the question on soy(a), however, for the general health concerns about this substance. You may like to limit your intake for health, not weight, reasons.