Proteins, essential elements in the body, are part of the basic structure of the bones and tissues (muscles, ligaments, skin, nails...) and many (such as hemoglobin, enzymes, hormones, antibodies, etc.) fulfill functions that are vital to life . You can get protein from animal or vegetable foods. If you just eat a single food, then it is animal products that will give you the most protein; but if you combine certain foods, then the amount of proteins available for absorption is higher. That is what happens, for example, when grains are combined with legumes. Perhaps this is why the traditional diet in much of the world is based on rice or corn (maize) with beans or lentils.
Fats allow your body to store energy, are the building blocks of cell membranes and some hormones... There are both animal and vegetable fats. The building blocks of fats are fatty acids, which may be unsaturated or saturated. Both are necessary, but too much saturated fat is harmful to the body, and some unsaturated fats can also be harmful to a person if they have a vitamin E deficiency.
As far as diet goes, the most important thing to know about fats may be the ratio of unsaturated/saturated fat: the higher the ratio, the better. If we order the main dietary sources of fat in by their ratios of unsaturated/saturated fats, then roughly in order from lowest to highest: lamb, pork, beef, dairy, rabbit, eggs, chicken and poultry, fish, cereals, vegetable oils (except for palm and coconut oils, which contain a higher proportion of saturated fats), avocados, nuts and seeds. Thats why you should try to get more fats from vegetables than from animals, and eat sparingly from those at the top of the above list.