Guide
Calorie counter for weight loss: setting a deficit you can actually hold
The arithmetic of weight loss is simple and widely known. The hard part is measurement and persistence — this page is about those.
Last reviewed August 30, 2026 by the Caloris nutrition product team.
Six steps that make calorie tracking work
Find your maintenance calories
Calculate your total daily energy expenditure from your height, weight, age, sex and activity level. This is the number of calories you burn on an average day and the baseline everything else is measured from.
Set a deficit you can hold for months
Subtract 250 to 500 calories a day from maintenance. That produces roughly 0.23 to 0.45 kg (0.5 to 1 lb) of weight loss a week. Larger deficits work faster on paper and fail faster in practice.
Set a protein floor before anything else
Aim for roughly 1.6 to 2.2 g of protein per kg of body weight per day. In a deficit, protein is what determines whether you lose fat or lose muscle, and it keeps hunger manageable.
Log every day, including the bad ones
The days you least want to log are the days the data matters most. Use a method fast enough that you will still do it when you are tired — photographing a plate takes seconds, searching a database does not.
Judge by weekly averages, not daily weigh-ins
Weigh yourself at the same time each morning and compare this week's average to last week's. Day-to-day fluctuations of 1-2 kg from water, salt and digestion are normal and mean nothing.
Adjust by about 10% after three flat weeks
If the weekly average has not moved in three weeks of consistent logging, reduce the target by roughly 10% or add activity. Do not halve your calories — small corrections keep the plan survivable.
Choosing your deficit
Bigger is not better. The deficit that produces the most fat loss over six months is rarely the one that produces the most in six weeks, because aggressive cuts drive muscle loss, hunger and abandonment.
| Daily deficit | Weekly loss | Sustainability | Appropriate for |
|---|---|---|---|
| 250 kcal | ~0.23 kg / 0.5 lb | Very high — barely changes how you eat | Small amounts to lose, or preserving muscle |
| 500 kcal | ~0.45 kg / 1 lb | High — the standard recommendation | Most people, most of the time |
| 750 kcal | ~0.68 kg / 1.5 lb | Moderate — hunger becomes a factor | Higher starting weights, short blocks |
| 1,000 kcal | ~0.9 kg / 2 lb | Low — hard to sustain past a few weeks | Supervised settings only |
Why calorie tracking usually fails in week three
The failure mode is remarkably consistent. Week one is meticulous. Week two is good. Week three has a late meeting, a restaurant meal nobody wants to itemise, and a tired evening — and the log has a hole in it. Once there is a hole, the numbers stop being trustworthy, and once they stop being trustworthy the habit has no purpose.
Notice that this is a friction problem, not a motivation problem. The fix is not more discipline; it is making the logging cheap enough that a tired person will still do it. That is the entire argument for photo-based logging: an AI calorie counter turns a two-minute task into a three-second one, and a three-second task survives a bad day.
Protecting muscle while you lose fat
- Hit protein daily. 1.6–2.2 g per kg of body weight. If you are carrying a lot of excess fat, calculate against your target weight rather than your current one.
- Keep resistance training in. Strength work is the signal that tells your body to hold onto muscle in a deficit; cardio is not a substitute for it.
- Do not rush. Loss faster than about 1% of body weight per week increasingly comes from lean tissue.
- Sleep. Short sleep raises hunger, lowers spontaneous movement and worsens body composition at the same calorie intake.
What to do when the scale stalls
- Check the log honestly for two weeks. Weekends included, drinks included, cooking oil included. Most stalls resolve here.
- Recalculate maintenance. A body 6 kg lighter burns less than it used to. Re-run the TDEE calculator.
- Check your activity level honestly. Most people select one step higher than their week justifies.
- Then, and only then, cut by 10%. Or add activity instead, which is often the more sustainable lever.
One thing that is not a stall: three days without movement. Water retention from salt, carbohydrate intake, training and hormonal cycles routinely masks a fortnight of genuine fat loss.
Setting it up
Start with the calorie calculator to get a target, split it with the macro calculator, and if you are new to tracking, read how to count calories for the practical habit side. Then pick a logging method fast enough to survive week three.
Caloris is a wellness and nutrition tracking app, not a medical device, and nothing here is medical advice. If you have a health condition affected by diet, or a history of disordered eating, speak to a doctor or registered dietitian before starting a calorie deficit.
Frequently asked questions
Does counting calories actually work for weight loss?
Yes, when it is done consistently. Weight loss requires taking in less energy than you expend, and tracking is simply the mechanism for knowing whether that is happening. Studies of self-monitoring consistently find that people who log their food lose more weight than those who do not, and that the frequency of logging predicts the result better than any particular diet.
How big should my calorie deficit be?
250 to 500 calories a day below maintenance for most people, producing about 0.23 to 0.45 kg (0.5 to 1 lb) of loss per week. Larger deficits are appropriate at higher starting weights, but they increase muscle loss, hunger and the chance of abandoning the attempt. Never go below roughly 1,200 calories a day for women or 1,500 for men without medical supervision.
Why am I not losing weight in a calorie deficit?
In almost all cases the deficit is not as large as it appears. The two usual causes are under-recorded intake — cooking oils, sauces, drinks, tastes while cooking and weekend meals that never get logged — and an over-estimated activity level inflating the maintenance figure. Log everything for two weeks including weekends before concluding the maths is wrong. Genuine plateaus also occur because a lighter body burns fewer calories, so recalculate after every 5 kg lost.
How long does it take to see results from calorie counting?
Scale weight can move within a week, though the first drop is largely water and glycogen rather than fat. A meaningful fat-loss trend takes three to four weeks to separate from normal fluctuation. Judge progress on a four-week window, not a four-day one.
Do I need to track macros as well as calories, or is calories enough?
Calories determine whether you lose weight. Macros determine what the loss is made of and how you feel during it. If tracking both feels like too much, track calories and set a single protein target — that combination captures most of the benefit without the overhead of managing three numbers.
What is the best calorie counter app for weight loss?
The one you will still be using in three months. Practically, that means the fastest logging method you can find, since speed is what determines whether the habit survives. Photo-based AI trackers such as Caloris log a meal in about three seconds; database apps are more precise for packaged food but slower for home cooking. Many people use both, scanning barcodes for packaged items and photographing everything else.
Should I eat back exercise calories when losing weight?
Generally no. If you chose an activity level that already includes your training, the exercise is counted in your maintenance figure and eating it back double-counts. Fitness trackers also tend to overestimate calories burned, sometimes considerably. If you add anything back after an unusually hard session, add a portion rather than the whole amount.
Make logging cheap enough to survive a bad week
Caloris logs a meal from a photo in about three seconds, so the habit holds on the days you would otherwise skip. Free on Google Play.
- Free to download
- Photo, barcode or text logging
- No credit card to start
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