Even though carbs are the body's major source of energy, fat is the most highly concentrated source of energy, over carbohydrates and proteins. (lovingfit.com)
Meat meals, however, are already cooked so their volume isn't going to change much — this makes them a much more highly concentrated source of protein than fresh meats! (pawster.com)
The most concentrated sources of protein is found in animal foods, such as chicken, beef, fish, shrimp and eggs. (healthyeating.sfgate.com)