Counting calories in: labels, weighing and home cooking
Counting calories doesn't have to be perfect. It has to be honest and consistent. Most of the gap between what people log and what they really eat comes from a few predictable places, and a cheap digital kitchen scale closes most of it.
Reading a food label
UK food labels give the energy per 100g (or 100ml), and often per portion too. A few things to know:
- Use kcal, not kJ. Labels show both. Kilocalories are what everyone means by calories; kilojoules are about four times bigger.
- Trust the per 100g figure. The label's portion is often smaller than what people really serve. A 30g bowl of cereal is a lot smaller than most pours.
- Do the sum: kcal per 100g ÷ 100 × the grams you ate. 375 kcal per 100g of oats, for a 40g bowl, is 150 kcal.
- Traffic lights are about health, not calories. The red, amber and green colours on the front cover fat, sugar and salt. The reference intake percentages assume 2,000 kcal a day, which may not be your number.
Weigh it, at least at first
People are poor at judging portions by eye, especially of foods that pack a lot into a little: pasta, rice, cereal, cheese, nuts and nut butters. A heaped spoonful of peanut butter is often twice the 15g the label assumes. A digital kitchen scale with a tare button, which zeroes it with the bowl on, costs a few pounds and makes weighing take seconds.
You don't have to weigh everything forever. After a few weeks you'll know what 75g of pasta looks like. Keep weighing the calorie-dense foods, where a small misjudgement costs the most.
Raw or cooked?
Pasta, rice and oats soak up water as they cook, and meat loses it. The calories stay the same while the weight changes a lot, so a figure for dry pasta used on cooked pasta overcounts by more than double. Match the figure to how you weighed it: most packets give dry weights, so weigh those foods before cooking.
For a big batch, weigh the whole pot once it's cooked, then weigh your portion out of it.
Home cooking
For anything made of several ingredients, add up each one, including the oil, then divide by the number of portions. If the portions aren't equal, weigh the finished dish and your share of it. The meal calculator does the sums, splits the total into portions and saves the meals you make often.
The calories that slip through
The main meals usually get logged. What gets missed is everything around them:
- Cooking oil and butter. A tablespoon of oil is about 120 kcal, and a free pour is often two or three.
- Drinks. Milky coffees, juice, fizzy drinks and alcohol. A pint of 4% lager is around 180 kcal.
- Sauces and dressings. A tablespoon of mayonnaise is around 100 kcal.
- Bits and pieces. Tasting while cooking, the children's leftovers, a handful of nuts (around 180 kcal for 30g), the biscuit with a cup of tea.
None of these feel like eating, which is why they're easy to forget. As the first chapter covers, people who struggle to lose weight often eat far more than they record without realising it.
Eating out
In England, cafés, restaurants and takeaways with 250 or more employees have had to show calories on their menus since April 2022, so a lot of chain food is easy to log. For independent places, find a similar dish from a chain, or make a generous guess. A rough figure on the high side is far better than nothing.
Close enough is good enough
Every calorie figure is an estimate, from labels to your watch. What matters is that your errors are consistent. If you find your maintenance calories from your own log, small habits like rounding down a portion are already built into the result.
The thing that really throws a week out is a blank day. If you can't count something properly, log a rough total for the day. The tracker only needs one number for calories in each day, so a best guess takes seconds.
Questions
Should I weigh food raw or cooked?
Weigh it in the same state as the nutrition figure you are using. Most labels for pasta, rice and oats are for the dry weight, so weigh those before cooking.
Do I need to count calories in drinks?
Yes. Milky coffees, juice, fizzy drinks and alcohol can add several hundred calories a day. Water, black tea and coffee, and diet drinks have little or none.
Is it kJ or kcal on food labels?
UK labels show both. Kcal is the figure people mean by calories, and kJ is about four times larger, so use the kcal figure.
What if I cannot find the calories for something?
Log your best estimate and lean towards the high side. A rough figure keeps the week complete, and a missing day hides more than a slightly wrong one.
Sources
- NHS. How to read food labels.
- Department of Health and Social Care. Calorie labelling in the out of home sector.
- Lichtman SW, Pisarska K, Berman ER, et al. Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. New England Journal of Medicine, 1992; 327(27): 1893–1898.
This guide is general information, not medical advice. If you have a health condition, are pregnant, or have a history of disordered eating, talk to your GP or a registered dietitian before changing how you eat.