Deficitly
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Should you eat back your exercise calories?
It depends on how your calorie target was set. If it already includes your workouts, as Deficitly's does when you add them, or as an "active" activity level does, don't eat them back: they're already counted. If your target assumes you sit all day (as many diet apps do), eat back about half of what your app or watch reports, because those numbers usually run high and include calories you'd burn anyway.
Why your watch's number is too high
| Activity | Total | Extra | Already in your day |
|---|---|---|---|
| Brisk walking | 360 | 285 | 75 |
| Running, 10 min/mile | 700 | 625 | 75 |
| Cycling, moderate | 600 | 525 | 75 |
| Weight training | 265 | 190 | 75 |
| Padel | 450 | 375 | 75 |
| HIIT | 525 | 450 | 75 |
| Yoga | 175 | 95 | 75 |
Two things inflate the number. First, the total includes about 1 calorie per kg per hour that your body burns anyway: it's already part of your daily burn. Second, wrist devices often overestimate energy use; in one Stanford study none of seven devices was within 20%. Eating back a watch's total can wipe out a deficit. More in how accurate TDEE calculators are.
If your target already includes exercise
This is the case when you add your workouts to Deficitly (in the app or the maintenance calorie calculator) or when you pick "moderately active" in a classic calculator. Your workouts are averaged over the week and built into the number, so eat the same every day and don't add anything back.
If your app sets a "sedentary" target
Some apps give you a low base target and add exercise calories on the day (net calories). If you use one, eat back about half of what it adds. That roughly cancels out the overestimate and the resting calories, and keeps your deficit intact.
If you train hard
Hard training on too little food backfires: poor recovery, low energy, and for some, especially women, hormonal changes (sports medicine calls it relative energy deficiency in sport). If your workouts suffer, eat more on training days or slow your weight-loss pace. Protein and carbs around training help most; see the macro calculator.
Training days vs rest days
You can eat the same every day (simplest) or eat more on training days and less on rest days, as long as the weekly total is the same. Both work equally well for weight; pick what suits your appetite and schedule.
How many calories does your workout really add?
Use the box above, or the calorie burn calculator for any of 112 activities. Specific pages: running, padel, lifting weights. If you're eating less but not losing, double-counted exercise is a common reason: see calorie deficit but not losing weight.