Rhubarb

Food · Vegetable · Food, Typed Supps

A very low-calorie, high-fiber stalk vegetable with a distinctly tart bite.

Stage by stage

Intake (Chewing begins): Chewing breaks down the fibrous stalk.
Stomach (Passes largely intact): Being mostly water and fiber, it moves through with little digestion.
Small intestine (Vitamin C & potassium absorbed): The modest vitamin C and potassium content absorbs here.
Large intestine (Fermented by gut bacteria): Remaining fiber is fermented by gut bacteria and adds bulk that supports regularity.

Timing

Any meal; conventionally cooked with sugar or sweeter fruit to offset its natural tartness.

Time to effect

A day: Fiber’s effect on digestion and regularity shows up within about a day of eating it.

Allergens

None of the fourteen major allergens. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Keto, Low-FODMAP, Gluten-free.

In season

January to June in the northern hemisphere, July to December in the southern.

Satiety

The satiety index is measured on 240 kcal servings. At 23 kcal per 100 g that is 1.1 kg of this, which is not a serving anyone eats — so the index has nothing to say about it.

Environmental footprint

0.5 kg CO2e and 108 litres of freshwater per kg, matched to "Other vegetables" in Poore & Nemecek (2018), Science 360.

Cost band

Cheap — roughly £2.5 per kg, as a band midpoint rather than a price.

Key nutrients

Nutrition per 100g

Calories: 22.5
Protein: 1.5g
Carbohydrate: 1.7g
of which sugars: 1.7g
Fat: 0.2g
of which saturated: 0g
Fibre: 2.2g
Sodium: 12mg

Food vs. supplement

A 100g serve provides real fiber and bulk for only about 22 calories, plus vitamin C and potassium — benefits a fiber supplement alone doesn’t replicate.

Kitchen tip

Stew with a little sugar or pair with sweeter fruit to balance the tartness — never eat the leaves.

Common myth

“Rhubarb is poisonous.” In reality: Only the leaves are toxic, due to concentrated oxalic acid. The stalks, which is what’s eaten, are safe — though still worth moderating if you’re prone to kidney stones.