What the Volume Index measures

The Volume Index scores any food on a single question: how much food do you physically get per calorie?

This is the index that most directly answers the question people actually ask when they are trying to eat well without feeling deprived: how much can I eat within my calorie budget? A high-scoring food gives you a large physical quantity for a modest calorie cost. A low-scoring food delivers significant calories in a small physical quantity.

The index scores on a 0 to 100 scale. The floor is set at 10 kcal per 100 g — the approximate caloric density of the least calorie-dense whole foods, like cucumber and lettuce — which scores near 100. The ceiling is set at 900 kcal per 100 g — the approximate caloric density of pure fat, like oil — which scores 0. Everything else sits between these two extremes.

Why volume matters for satiety

The stomach is a physical organ. It responds to physical volume — how much food is in it — not just to calories. When you eat a high-volume, low-calorie-density meal, your stomach fills, stretch receptors activate, and satiety signals are sent to the brain before a significant calorie load has been consumed. This is the mechanism behind why a large bowl of vegetables leaves you feeling full on relatively few calories, while a handful of nuts delivers the same calorie count in a fraction of the physical volume and much less physical fullness.

This is also why caloric density is one of the most useful variables for people who want to eat satisfying amounts of food without exceeding their calorie budget. The strategy is not to eat less — it is to eat more food that takes up more space per calorie.

A note on the name

Volume is the conceptually correct term — we are measuring how much physical space a food occupies per calorie. But nutrition labels report weight in grams, not volume in millilitres or cubic centimetres. We use weight as a practical stand-in for volume throughout this index. The two are related but not identical — a gram of oil and a gram of broccoli occupy very different physical spaces despite weighing the same. In practice, foods with low caloric density per gram also tend to have low caloric density per unit of physical volume, so the approximation holds well enough for everyday use.

An important distinction: this index is neutral

Like the Fat Index, the Volume Index does not carry a directional verdict in the way that Protein and Fibre do. A high score is not unambiguously better. It is most useful for a specific purpose: maximising physical food quantity within a calorie budget.

For foods that are not primarily eaten for volume — a drizzle of olive oil, a handful of almonds, a piece of cheese — a low Volume Index score is simply an accurate description of what that food is. It is calorie-dense. That is not a character flaw. Almonds score around 18 on this index and around 89 on the Fat Index and around 35 on the Protein Index. They are not a volume food. They are a nutrient-dense food eaten in small quantities. The Volume Index tells you one true thing about them. The other indexes tell you other true things.

How to read your score

The scale uses a square root curve rather than a logarithmic or sigmoid one. The square root curve produces meaningful score separation in the low-to-moderate caloric density range — roughly 10 to 400 kcal per 100 g — where most daily food decisions happen. It compresses scores at the high end, where the signal is simply “this is calorie-dense” without needing to distinguish finely between different high-density foods.

Two notes are built into the calculator:

A high note appears above a score of 85, corresponding to roughly below 60 kcal per 100 g. This is the range of most vegetables and many fruits — foods that genuinely earn the description of high-volume, low-calorie. The note is positive and confirms that this food is an effective tool for eating satisfying quantities on a modest calorie budget.

A low note appears below a score of 45, corresponding to roughly above 400 kcal per 100 g. This is the range of cheese, nuts, seeds, and oils. The note is not a penalty — it explicitly names several of these foods as nutritionally valuable — but it flags that volume is not their value proposition and that using them as primary meal components rather than additions will consume the calorie budget quickly.

Reference points

Cucumber — 98
Broccoli — 95
Apple — 92
Chicken breast — 82
White rice, cooked — 80
Whole eggs — 77
Salmon — 73
Cheddar cheese — 45
Almonds — 18
Pure oil — 0

How to use this in practice

In label mode, enter the weight in grams and the calories for that weight as they appear on the label. The calculator converts this to kcal per 100 g internally.

In quick mode, enter the kcal per 100 g figure directly — this appears as a standard column on most Singapore nutrition labels and requires no calculation on your part.

The Volume Index is most useful when read alongside the Protein and Fibre indexes. A food that scores well on all three — high volume, high protein, high fibre — is likely to be genuinely satisfying relative to its calorie cost. This combination is the foundation of the Satiety Index, the first of the second-tier composite indexes, which will weight these three variables together into a single score designed to answer the most practical question in everyday eating: will this food keep me full?

What comes next

With all five base indexes now complete — Protein, Fat, Fibre, Sugar, and Volume — the library has its foundation. The second tier begins with the Satiety Index, which combines Protein, Fibre, and Volume into a single composite score. From there, the library will expand to category-specific indexes — Dessert, Snack, Breakfast Product, Drink, Bread and Grain, and Dairy — each calibrated to the specific nutritional question that matters most for that food category.