Whole egg vs egg white
Most of the fat and many micronutrients are in the yolk. Most of the pure lean protein is in the white. That means whole eggs are more nutrient-dense, while egg whites are easier to fit into a low-fat, high-protein target.
A common tracking approach is to combine both: for example, two whole eggs plus extra egg whites. This keeps flavor and micronutrients while increasing protein without adding much fat.