Carbohydrates, fats and protein are all macronutrients, i.e., the part of our diet that provides energy and the building blocks our bodies use for growth and maintenance. If we don't need to eat carbs, what macronutrients DO we need to eat?
Good fats and good proteins.
Good fats are (obviously) not the transfats. We also have to be careful with mono- and polyunsaturated fats, found in liquid vegetable oils. These become rancid within days to weeks and turn into forms that cause oxidative damage to our bodies. A better choice is the saturated fat found in animal fat and butter. An even better choice is the medium chain triglycerides found in coconut oil.
Good proteins are complete proteins. Proteins are made of long chains of amino acids. We can make some of the amino acids through intermediary metabolism, but some are essential amino acids and must be taken in as food. Excellent souces of complete protein include eggs, whey protein, cheese, meat and fish.