Deficitly
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What is CICO, and what are net calories?
CICO stands for calories in, calories out: if you eat fewer calories than you burn, you lose weight; more, and you gain. "Calories out" is your TDEE, about 1,910 a day for an average-sized American woman at 6,000 steps. Net calories is what diet apps show as food eaten minus exercise burned: eat 2,000 and burn 400 in a workout, and your net is 1,600. Net calories only make sense if your target doesn't already include that exercise.
Calories out: where they go
| Part | Calories | Share |
|---|---|---|
| Resting burn (BMR) | 1,420 | 74% |
| Daily life | 140 | 7% |
| Steps | 150 | 8% |
| Digestion | 190 | 10% |
| Total | 1,910 | 100% |
You can change calories out mostly through movement: steps and daily activity, then workouts. Resting burn follows your size and age. More in how many calories you burn a day and BMR vs TDEE.
Calories in
Everything you eat and drink, including oils, sauces and drinks. Food labels are allowed some margin of error, and most people undercount by 10–30%, which is why calories in is usually the less precise side. Digesting food uses about 10% of it (more for protein: see thermic effect of food), which calculators include on the calories-out side.
What are net calories?
Many diet apps start you on a low "sedentary" target and add the calories from logged exercise: net calories = food − exercise. Eat 2,000, burn 400 in a logged workout, and your net is 1,600; the app compares that with your target. Two cautions: workout calories in apps are usually the total, including the calories you'd burn anyway, and wrist devices often overestimate. If your target already includes your workouts, as Deficitly's does, ignore net calories and simply eat your target. See should you eat back exercise calories?
Does CICO really work?
Yes: over weeks, your weight follows the balance between what you eat and what you burn. The criticisms are usually about something else. Calorie counts are imprecise on both sides; hormones, sleep and stress change appetite and how much you move, which shifts the balance; and the type of food matters for how full you feel and how much muscle you keep. All of that works through calories in and calories out rather than around them. Protein and fibre help most: see what are macros?
Using CICO in practice
- Find your calories out: the maintenance calorie calculator.
- Set calories in a little below it: the calorie deficit calculator shows gentle to fast paces.
- Track roughly for 3–4 weeks and compare with your weight trend; adjust by 100–200 calories if needed.