How to count calories: accurately enough, without obsessing
Okay, you’ve convinced me, let’s try it. So how do I count?
Short answer: get a food tracker and a kitchen scale. Weigh the calorie-dense foods (oils, nuts, sweets, bread, grains, meat), log packaged food from the label, and don’t bother with lettuce or plum pits. Your numbers don’t need to be perfect. They need to be consistent.
If you’re not convinced yet, start with part 1: does calorie counting work?
What you need to count calories
You’ll need:
- patience
- following instructions to the letter
- any food tracker you find pleasant to use. Apart from how easy it is to use, trackers differ in one main thing: the quality of their food database. Pick one with a good database for the food sold where you live.
- a kitchen scale. S-tier: the one thing on this list you can’t skip
Do you need to weigh your food?
How many steps is it from your apartment door to the street? How many matches are in a matchbox? It’s hard to answer exactly, but you can try to estimate and count, because these are things from the physical world.
An apple is also from the physical world. How many calories are in an apple? Calories are a measure of energy and you can’t see them, so you can’t answer the way you would with the matches. Only a calorimeter knows the answer: a special device that burns the food and measures the heat. A person has to google it (or look the number up in an app).
The next question: how much does an apple weigh? Apples vary a lot. A small one can weigh 50 g (under 2 oz), and one that was well and generously fertilized can weigh 250 g (about 9 oz). That’s a fivefold spread, and a very high error. But apples on the whole forgive mistakes, because they have few calories. A small apple can have ~25 calories, a big one ~130. With a daily limit of 2,000 calories, getting an apple wrong by a few dozen calories isn’t much of a problem.
But how many calories are in a portion of rice or pasta? In a Snickers or a bag of chips? 100 g (3.5 oz) of cooked rice is ~130 calories. 250 g (8.8 oz) is ~330 calories. 200 calories isn’t much in everyday life. But when you’re losing weight, it can easily be ~15% of your daily calories. Here’s the question: without practice, can you tell by eye how much a portion of rice weighs? Just for fun, I ran this test on different foods with myself and with different people. The results are discouraging: nobody gets it right.
Unfortunately, eyeballing just doesn’t work if your eye isn’t trained and you have no experience with the thing you’re estimating. People are very bad at estimating anything at all (IT project managers will back me up). That’s why a kitchen scale is a must while you’re losing weight. The good news is that with time (a couple of months) your eye gets trained, and you can spend less time weighing. But for now, that’s how it is, and you’ll have to weigh everything.
“Weigh everything” means everything in the table below. The more 💥, the more accuracy matters:
| Food | Impact |
|---|---|
| Calorie bombs: vegetable oils and butter, nuts, honey, dried fruit | 💥💥💥💥💥 |
| Alcohol | 💥💥💥💥 |
| Candy, chocolate, protein bars, desserts | 💥💥💥💥 |
| Bread, pastries | 💥💥💥 |
| Rice, pasta, oats, quinoa, etc. | 💥💥💥 |
| Sauces | 💥💥💥 |
| All liquid calories: juices, lemonades, smoothies, milk | 💥💥 |
| Cheese and dairy | 💥💥 |
| Meat, fish | 💥💥 |
| Seafood | 💥 |
| Fruit, vegetables, berries | 💥 |
| Supplements (for example, protein powder or psyllium husk) | 💥 |
How to use a kitchen scale (and its tare button)
There are three ways:
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Zero the scale, put the food on it, read the weight. Handy for whole foods like apples or plums that you eat whole or almost whole.
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Put a plate on the scale, zero it (this is the tare button), then put the food on the plate. Handy for weighing almost any food, like rice or chicken breast.
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Weigh the package instead of the food. Very handy for dry foods like flour, for semi-liquid foods like honey or tomato paste in a tube, and for any liquid. A scale doesn’t always pick up light foods that pour onto a plate slowly, a little at a time. It’s also a handy way to weigh the oil you pour into a frying pan: you’re not going to put a hot pan on the scale.
How it works: put the package on the scale, zero it, squeeze or pour the food out of the package, put the package back on the scale, and note the negative number. That’s how much you used.
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1Put the package on the scale and press zero.
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2Pour or squeeze out as much as you need.
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3Put the package back. The negative number is how much you used.
What you can log without weighing
You don’t have to weigh these separately. Just log them:
- Anything that has a serving and a weight on the package, and that you’ll eat in one go: a protein bar, a Snickers, a can of Pringles, a 12 oz can of Coke, a pack of blueberries, a yogurt.
- Eggs: you can simply log them by the piece.
- A portion that splits roughly evenly over two days. For example, if I buy a 1 lb (450 g) pack of chicken breast and eat it over two days on my own, I just log half a pound (225 g) on each day and don’t calculate anything.
- A portion you can easily split in your head. If you eat a 1 lb (450 g) pack of chicken and your partner eats about a third of it, log two-thirds (300 g) for yourself. If a steak is cut into two even pieces, log half.
What you don’t need to log at all
- Water, unsweetened tea, black coffee without milk or sugar, Coke Zero.
- Leafy greens like spinach, arugula or lettuce. It’s hard to eat a lot of them, they’re awkward to weigh, and there’s little point.
Should you round, or weigh to the gram?
Some people in the fitness crowd insist that you always log every food to the gram, subtract the cores from apples and weigh the pits from plums. Partly this comes from people being sloppy with counting.
But personally, I think micro-optimizations like plum pits are a waste of energy: nobody ever became a millionaire by saving on toilet paper. Vegetables, fruit and berries, as a class of foods, allow quite a big error. Eating so many apples that they really add up to a high total error is a good problem to have. So rounding to the nearest convenient number is fine.
On the other hand, if your calories are very low, or you need very high accuracy (for example, you want a very low body fat percentage for looks or for a competition), counting to the gram is justified and necessary.
Still, do count oranges, bananas and watermelons without the peel. And the high-calorie foods at the top of the list above don’t forgive mistakes. Count them as accurately as you can.
Food you can’t count exactly: fast food, pastries and desserts
Food that you can’t count exactly is a category of its own:
- Tasty but calorie-dense dishes with many ingredients: gyros, burgers, pizza, Subway subs
- Croissants and other pastries
- Desserts of every kind
- All restaurant food more complicated than a steak or a tomato and cucumber salad
With this kind of food, there are two approaches:
- find a similar entry and always log that one
- estimate the “price” of fast food and burgers once, as a set number of calories, and reuse it every time
The main problem with this kind of food is a lot of calories per square millimeter. That doesn’t make burgers, croissants and eclairs evil. But there are a few problems with them:
- Desserts and fast food have a lot of calories and few of the nutrients you need, both at once. In your daily calories, this food just takes up room without adding protein, healthy fats, fiber or micronutrients. And a piece of cake can easily be 20–33% of your daily calories.
- Point 1 means it doesn’t fill you up. If you eat a salad and a piece of meat, or a piece of cake with the same calories, you’ll want to eat again much sooner after the cake, guaranteed. (In one study of 38 foods with the same calories, the croissant was the least filling. Boiled potatoes were seven times more filling.)
- Desserts and fast food are often bought, and it’s almost impossible to count their real calories. You’ll never know how much butter, flour and sugar is inside. And you’re better off not knowing.
For these reasons, many diets fully cut out “sweets, fatty food, desserts, fast food and pastries”. True, it’s easier to ban a whole class of foods than to explain the nuances. I’m not a fan of bans, so I think you can have anything, but everything in moderation. As Ray Dalio puts it: you can have virtually anything you want, but you can’t have everything you want. There’s no point in never eating cake, but you can’t eat only cake.
A rough estimate:
| Food | Calories |
|---|---|
| Bread | ~200–300 per 100 g (3.5 oz) |
| A chocolate bar like a Snickers | 250–400 per bar |
| Almost any pastry or dessert | 300–500 per 100–130 g (3.5–4.5 oz) serving |
| A serving of fries with a sauce | 350–500 |
| A beef burger | ~700–1,000 |
| A chicken burger | ~400–600 |
| A whole pizza | 1,300–2,000 (the range here can be huge) |
You can count fast food and desserts like this:
- look for the exact item in the app. For example, almost the whole McDonald’s or KFC menu is in every tracker
- if it’s not in the tracker, AI most likely knows it. Log it by voice, or take a photo where the brand or the name of the food is visible
- if there’s no exact item, take any similar one that fits the calories above. When you’re losing weight, it’s best to add 10–20% on top for error
Restaurants and delivery have a part of their own: eating out and delivery. So do drinks: calories in alcohol.
Sources
- A satiety index of common foods. Holt SH, Miller JC, Petocz P, Farmakalidis E. Eur J Clin Nutr. 1995. (PubMed)