Glycaemic index: how to choose your carbs

7 min read · Last updated 12 June 2026

The question we get most often is not “what am I allowed to eat” but “can I still eat rice”. The answer is almost always yes. What changes is the form, the portion, and what keeps it company on the plate.

What the glycaemic index measures

The glycaemic index (GI) ranks how quickly the carbohydrate in a food raises blood glucose, compared with pure glucose. The faster the rise, the higher the number.

• Low GI, 55 or under. Legumes, non-starchy vegetables, apples, pears, boiled sweet potato, whole oats.
• Medium GI, 56 to 69. Brown rice, sweetcorn, ripe banana, wholegrain bread.
• High GI, 70 or above. Soft white rice, chips, white bread, rice porridge, sweet drinks.

Four ways to flatten the spike without changing the menu

1. Cool your carbs. Cooked rice and potato that have cooled form resistant starch, which digests more slowly than food served steaming hot.
2. Keep fibre on the plate. Vegetables, beans, or fruit with the skin on slow glucose absorption. Aim for 25–30 grams of fibre a day.
3. Pair with protein and healthy fat. Tempeh, tofu, fish, eggs, or a handful of nuts flatten the curve.
4. Walk 10–15 minutes after eating. Working muscle takes up glucose without waiting for extra insulin.

What GI cannot tell you

GI values are measured in a laboratory, on people eating a single food after fasting. Your plate is not like that. Ripeness, cooking time, processing, even how fast you chew all move the number. Treat GI as a compass, not a scale.

The honest way to learn how your body answers a given meal is to measure it: log what you ate, then check your blood sugar two hours later. Ten of your own readings beat a hundred GI tables on the internet.