5 foods under 5 calories per 100 g — and why they are all drinks
Under 5 kcal per 100 g there is effectively nothing to eat — only things to drink. That is the honest finding, and it is worth saying before the list, because the “zero calorie foods” articles that circulate are mostly wrong about their own premise. Celery is 14 kcal per 100 g. Cucumber is 15. Iceberg lettuce is 14. Low, and nowhere near zero.
Here is the band as it really is:
| Food | kcal per 100 g / 100 ml |
|---|---|
| Water, still or sparkling | 0 |
| Plain brewed tea, no milk or sugar | ~1 |
| Black coffee, brewed | ~1–2 |
| Diet and zero-sugar soft drinks | 0–1 |
| Dashi or clear strained stock | ~2–4 |
Why nothing solid gets this low
Anything with cell walls carries some carbohydrate, and carbohydrate is 4 kcal per gram. Cucumber is about 96 per cent water and still holds 3.6 g of carbs per 100 g, which is where its 15 kcal comes from. To land under 5 you need to be roughly 99 per cent water, and the only things that are either come out of a tap or were engineered to.
So the band is not a shopping list. It is the answer to a different question: what can you consume in quantity without it counting?
What it is for: drinks, not food
Drinks are where the easiest calories in a day hide, because liquid energy barely suppresses appetite at all. The comparison that matters is not water against celery, it is a drink against the drink it replaces:
- 500 ml cola: about 210 kcal
- 500 ml of the zero-sugar version: about 1 kcal
- A large flavoured latte: 250–400 kcal
- The same cup, black: 2–4 kcal
Nothing else in a day of eating offers a 200 kcal swap you will not notice. Coffee and tea are ~1 kcal in the cup; what turns them into a meal is the milk, the syrup and the sugar. Green tea is the same arithmetic.
On the energy-balance question specifically, zero-calorie sweeteners are 0 kcal and substituting them for sugar reliably lowers intake. That is a narrow claim about calories, not a health endorsement.
Stock is the one with a catch
Clear stock earns its place here because soup is the most reliably filling format there is for its calories — see high-volume, low-calorie foods. A dashi or a properly strained stock is 2 to 4 kcal per 100 ml and makes a bowl of vegetables feel like dinner.
The catch is sodium, not energy. Some bouillon cubes and concentrates carry 600–900 mg of sodium per 100 ml of made-up broth. The calorie figure is genuinely near zero; the salt figure is not, and it is the one worth reading on the packet.
The negative-calorie claim does not survive
The appealing version of this band is that some foods cost more energy to digest than they supply. They do not. The thermic effect of food is roughly 5 to 10 per cent of the energy eaten for carbohydrate, which on a 15 kcal portion of celery is about one kilocalorie. The net stays positive — trivially, but positive. The cucumber page works through the same myth in more detail.
The practical conclusion survives the mechanism being wrong, which is why it is worth correcting rather than repeating. Whether a plate of cucumber is 15 kcal or 14 is not a number anybody needs to manage.
The honest limit
There is no protein here, no fibre, and no satiety beyond stomach stretch, which fades within an hour or two. Water before a meal takes the edge off; it does not replace a meal, and drinking more of it is not a weight-loss method.
What this band does is remove the cost of volume, so that the food you do eat can be chosen on other grounds. The first rung with actual solid food on it is under 10 kcal per 100 g — and every item there is manufactured, which tells you something about how hard this is.
The rest of the ladder
Under 5 · under 10 · under 20 · under 30 · under 50 · under 100 · under 200 · under 300 · under 400 · under 500
Figures are typical values from USDA FoodData Central and product labels, and vary by brand and preparation. General information, not medical advice.