What the protein Index measures

The Protein Index scores any food on a single question: how much protein does it deliver relative to its calorie cost?

Protein is the most satiating of the four macronutrients. It takes the longest to digest, which means it keeps you full for longer than an equivalent number of calories from carbohydrates or fat. It also supports muscle maintenance — relevant not just for people who train, but for anyone who wants to preserve lean body mass as they age. And it is the macro most consistently underpresent in convenient, packaged, and processed food options — which means most people eating a typical modern diet are getting less of it than they need.

The index scores on a 0 to 100 scale. A score of 100 represents the theoretical ceiling — a food where every single calorie comes from protein, delivering 25 g per 100 kcal. No real food reaches this. In practice, the highest-scoring whole foods are things like egg whites, white fish, and chicken breast, which come in around 90 to 95. These are your benchmarks for excellent protein density.

How to read your score

The scale uses a logarithmic curve rather than a straight line. This is intentional. The difference between a food with 2 g of protein per 100 kcal and one with 8 g is nutritionally significant — that gap represents a meaningful improvement in satiety and muscle support. The difference between 20 g and 22 g per 100 kcal is much less important in practice. The logarithmic curve reflects this: it spreads scores apart at the low end of the spectrum, where differences matter most, and compresses them at the high end, where they matter least.

What this means in practice: a food scoring 50 is not half as good as a food scoring 100. It means the food is delivering protein at a rate that sits well below the best available whole food sources. A jump from 30 to 60 on this index represents a more meaningful nutritional improvement than a jump from 70 to 90.

Reference points

These are approximate scores for common foods to give you a sense of the scale:

Egg whites — 96
Chicken breast — 94
White fish (cod, tilapia) — 95
Whole eggs — 81
Cottage cheese — 78
Greek yoghurt, full fat — around 70
Salmon — 76
Lentils, cooked — around 55
Cheddar cheese — around 48
Almonds — around 35
White bread — around 30
White rice, cooked — around 20

A low score is not automatically a problem

A low Protein Index score means this food is not a strong source of protein relative to its calorie cost. It does not mean the food is poor. Vegetables, fruits, and many whole grain foods score low on this index and are nutritionally valuable in other ways — through fibre, micronutrients, and volume. The index is measuring one dimension only.

Where a low score becomes worth paying attention to is when the food in question is a packaged product claiming to be a meal replacement, a protein snack, or a high-protein option — and the score suggests otherwise. It is also worth noting when the food is your primary or only protein source in a meal, in which case pairing it with something higher on this index will improve the overall nutritional quality of what you eat.

How to use this in practice

In label mode, enter the protein and calorie figures exactly as they appear on the nutrition label for your serving size or for the full product — whichever is more relevant to how you are eating it. If you are cooking and weighing ingredients, the weight field is there for your reference and does not affect the score.

In quick mode, enter the protein per 100 kcal figure directly. Many nutrition labels in Singapore display values per 100 g alongside per serving — if your label shows per 100 g, you will need to know the calorie density of the food to convert to per 100 kcal. Label mode handles this conversion for you automatically.

What comes next

The Protein Index is the first of five base indexes. The others — Fat, Fibre, Sugar, and Volume — each measure a different dimension of nutritional value using the same scoring framework. Used together, they give a more complete picture of any food than any single number can. The second tier of indexes combines these individual scores into context-specific composites — including a Satiety Index that weights protein, fibre, and volume together as the three variables most directly linked to feeling full. Take a look at the Fat Index next.