Meat and dairy are major sources of protein and cholesterol.
Proteins are literally the, "building blocks of life." Meats and cheeses are packed with protein. Your brain is composed mostly out of cholesterol! (Sea) salt is vital for getting essential minerals, and is also responsible for proper neuron (brain and nervous system) conductivity.
But all we hear is how people shouldn't eat too much red meat, cholesterol is bad, eggs are bad, and salt is bad. Why? Because they want to either kill you, or get you hooked on some medication.
Never be afraid to ask simple questions.