Compare foods on nutrition per serving.
Two labels are rarely comparable as printed, because manufacturers choose their own serving sizes. Normalising protein to a fixed 100 kcal of energy removes that distortion and answers the question shoppers actually have: for the same calorie cost, which product delivers more protein. Anything above roughly 10 g per 100 kcal is a genuinely protein-dense food.
Protein density per energy
Protein per 100 kcal = protein g / calories x 100
These figures are population-average estimates for general planning only and are not medical or dietetic advice. Individual energy and nutrient needs vary widely with body composition, activity, medication and health status. Consult a qualified health professional or registered dietitian before making significant changes to what you eat, and especially if you are pregnant or breastfeeding, are under 18, or have a medical condition or a history of disordered eating.
Serving sizes on labels are chosen by the manufacturer and often differ between competing products, which makes per-serving figures misleading. A fixed energy basis puts both products on the same footing.
Skinless chicken breast and white fish are around 20-22 g per 100 kcal, plain low-fat Greek yoghurt around 10-12 g, lentils around 7-8 g, and bread or breakfast cereal typically 3-4 g.
Yes — enter fiber, sugar or sodium in place of protein and read the result as grams or milligrams of that nutrient per 100 kcal. The arithmetic is identical.