You read a recipe that says "one portion of rice" and stare at the pan. How much is that? A kitchen scale answers it exactly, but you will not carry one to a restaurant, a friend's dinner or a work canteen. Your hand, though, is always with you. Health bodies such as the British Dietetic Association and the British Heart Foundation use hand shapes to explain portions, so it is worth knowing how well they work and where they stop working.

Why portions are hard to judge

People tend to eat more when more is put in front of them. A 2014 review that combined many studies found that doubling a portion raised how much people ate by about 35% on average, and the effect was smaller when people paid close attention to their food. You do not need to be obsessive about this. It simply helps to have a rough picture of what a normal portion looks like, so a "big" one does not quietly become your default.

Try it: portions by hand

Pick a food group below. The hand and household measures come from the British Heart Foundation, the British Dietetic Association (BDA) and the NHS. They are indicative, not exact.

By hand

By spoon, piece or glass

In grams

Is your palm bigger or smaller than average?

Hands vary with body size. Cook a piece of fish or chicken breast, hold it against your palm until it covers the same area and thickness, and weigh it. The BDA's reference for a palm of fish is 140 g.

g

Hand sizes and food shapes differ. Use this as a starting point, then adjust to your appetite.

Build a plate with palms

Now try a dinner. Set how many palms of each food you would put on the plate. The picture shows how much of the plate each one takes, by area. This is a picture of space, not of weight or calories.

Eatwell Guide reference: fruit and veg, and starchy foods, each "just over a third" of what we eat over a day.

Your palm is a handy ruler, not a rule. Use it when there is no scale, and check it against a scale once to see how close it is.

Where hand measures fall short

Sources do not always agree. For starchy food, the BHF describes roughly a palm, while the BDA counts a portion in smaller units such as 2 to 3 tablespoons of boiled rice or pasta, or one slice of bread. Guidance counts "portions" across a whole day, and one meal can hold more than one. Calorie-dense foods like nuts, oils and cheese are small in volume but add up quickly, which is why those are measured with a thumb, spoon or matchbox rather than a palm.

Hands also cannot tell you how much oil went into the pan or how a dish was made. If you track your intake for a medical reason, or you are managing a condition, use a scale and ask your doctor or a registered dietitian what suits you.

A simple way to start

Choose one meal this week and measure it once with a scale, then compare it with your hand. After that, trust your eyes and your hunger. If you have a health condition, are pregnant or breastfeeding, take medication (especially for diabetes or blood pressure), or have or had an eating disorder, talk to a doctor or dietitian before changing how you eat. This guide is general information, not medical advice.

Sources