Do you need to count calories to lose weight? What the research says

Calorie counting has a bad name. People picture weighing every grain of rice, typing numbers into an app after every meal and feeling guilty about a biscuit. So it's fair to ask: do you really have to do this to lose weight? The short answer is no. The longer answer is that some kind of tracking makes it a lot easier, and it doesn't have to be painful.

The quick answer

• You don't have to count calories to lose weight. You do need to eat less energy than you burn, and there's more than one way to get there.
• Tracking helps most people. In studies, people who write down what they eat on most days lose more weight than people who don't.
• We're bad at guessing. Without any tracking, most of us eat more than we think.
• The best method is the one you'll keep doing. Rough tracking every day beats perfect tracking for one week.

Why calories still matter, even if you don't count them

Every way of losing weight works through the same thing: a calorie deficit. Low-carb, low-fat, intermittent fasting, "clean eating" and eating fewer meals out all help because they make you eat less energy overall, often without you noticing.

A big Stanford trial called DIETFITS shows this well. It put 609 adults on either a healthy low-fat or a healthy low-carb diet for a year. The groups were taught to eat whole foods and cut fat or carbs, not to hit a calorie number. Both groups lost weight: about 5.3 kg on low-fat and 6.0 kg on low-carb, a difference too small to matter. So yes, you can lose weight without counting. But the people in that study also had 22 group sessions with health educators over the year. That's a lot of support.

What the studies say about tracking

When researchers look at what separates people who lose weight from people who don't, writing down food comes up again and again.

• In the Weight Loss Maintenance Trial, nearly 1,700 adults followed the same 6-month program. They lost 5.8 kg on average, and keeping food records was one of the strongest signs of who lost the most. Those who kept records on most days lost about twice as much as those who kept none.
• A 2019 study tracked how long people actually spent logging their food online. It took about 23 minutes a day in the first month, but only about 15 minutes a day by month six. It got faster with practice. And the people who lost at least 5% of their weight logged in more often each day, about 2.4 times compared with 1.6.

The lesson from that second study is useful: it wasn't the time spent that mattered, it was logging often, close to when you eat. Quick and frequent beats slow and perfect.

Curious about a real meal? Tap Ask AIMS (bottom right) and type: "Roughly how many calories was my lunch today?"

Why guessing usually fails

If you've ever said "I barely eat and I still don't lose weight", you're not alone, and you're probably not lying either. A classic study from 1992 looked at people who said they couldn't lose weight on under 1,200 kcal a day. When the researchers measured what they really ate and burned, these people had under-reported their food by 47% and over-reported their exercise by 51%. Their metabolism was normal. Their estimates weren't.

This isn't about willpower. Food is hard to judge by eye. Cooking oil, drinks, sauces, snacks between meals and bigger portions at weekends are easy to forget. A little tracking simply makes those visible. Our post on why you're not losing weight goes through the most common hidden calories.

Ways to lose weight without strict counting

If counting every gram isn't for you, these approaches can still create a deficit. They work best when you also check your weight trend so you know they're working.

• Eat mostly whole, simple foods. In a 2019 NIH study, people ate about 500 kcal a day more on an ultra-processed diet than on a minimally processed one, even though both were offered freely and matched for things like sugar, fat and fibre. Whole foods tend to fill you up on fewer calories.
• Build plates the same way. Half vegetables, a palm-sized portion of protein, a fist of starch. It's not exact, but it keeps portions steady.
• Keep protein high. It keeps you full and protects muscle. See how much protein you need a day.
• Watch your drinks. Juice, soft drinks, sweet coffee and alcohol add up fast and don't fill you up.
• Plan meals out. Restaurant portions are usually bigger. Our guide to counting calories when you eat out has easy tricks.

When counting is worth it

Counting, even roughly, is most useful when:

• You've tried eating "healthy" and the scale hasn't moved in a few weeks.
• You're new to this and want to learn what normal portions look like. A few weeks of tracking can teach you a lot that sticks.
• You have a clear goal, like losing the last few kilos or eating enough to build muscle.

You don't have to do it forever. Many people track closely for a month or two, learn their usual meals, and then track more loosely. If you want a target to aim for, start with how many calories you should eat to lose weight.

One honest note: if tracking makes you anxious or obsessed with food, it's fine to stop and use the simpler methods above. And if you have a health condition, talk to a doctor or dietitian before changing how you eat.

How to make tracking less painful

• Log right after you eat, not at the end of the day, when you've forgotten half of it.
• Be roughly right, not perfect. A good estimate every day is worth more than a perfect one now and then.
• Save your regular meals. Most people eat the same 15 or 20 meals, so it gets quicker each week.
• Look at weekly trends, for both your calories and your weight, not single days.

Want a number for yourself? Ask AIMS: "How many calories should I eat a day to lose weight at my weight?"

The short version

• You can lose weight without counting calories, but you can't lose it without a calorie deficit.
• People who track their food on most days tend to lose more, and logging gets faster with practice.
• Most of us under-guess what we eat, so some tracking keeps you honest.
• Rough, frequent tracking beats strict, short-lived tracking. Pick the method you can keep up.

The hard part of counting is the typing. With AIMS you just text, snap or say your meal, and it works out the calories for you.