Formula, in Fat Loss
Food-to-Exercise Conversion Formula
Food-to-exercise conversion expresses food calories as activity time at a given MET. 1 MET = 1 kcal/kg/hour. A 75 kg person walking at 3.5 MET burns ~262 kcal/hour. Useful for reframing portion sizes; not a literal calorie-canceling guide because EPOC + appetite compensation alter real-world totals.
4 variables. Published May 14, 2026. By AI Fit Hub.
minutes_to_burn = food_kcal / (MET × mass_kg × 0.0175)
0.0175 = (1 kcal/kg/hr) / (60 min/hr)
Common MET values (Ainsworth Compendium 2011):
Walking moderate (5 km/h): 3.5
Walking brisk (6.5 km/h): 4.5
Jogging: 7.0
Running 10 km/h: 9.8
Cycling moderate (15-20 km/h): 7.5
Cycling vigorous (25+ km/h): 12
Swimming freestyle moderate: 8.3
Lifting weights moderate: 5.0 Variables
minutes_to_burn
Minutes of activity to burn food kcal
Output in minutes. The longer the activity, the more EPOC + appetite compensation muddy the answer — treat as theoretical not literal.
food_kcal
Food energy
Calorie count of the food. From a nutrition label or food database (USDA FoodData Central, MyFitnessPal). Be honest — most home portions are 20-40% larger than labeled.
MET
Metabolic Equivalent of Task
Activity intensity multiplier. 1 MET = resting energy expenditure ≈ 3.5 ml O2/kg/min. Walking is 3.5 MET (3.5× resting). MET values from Ainsworth Compendium are population averages with ±15% individual spread.
mass_kg
Body mass
Body weight in kilograms. Heavier people burn more calories per minute at the same MET because more tissue to move.
Step by step
- 1
Look up MET value for your chosen activity in the Ainsworth Compendium.
Cycling moderate (16-19 km/h on flat) = 7.5 MET.
- 2
Find food kcal from label or database.
Slice of pizza = 285 kcal.
- 3
Apply formula.
minutes = 285 / (7.5 × 75 × 0.0175) = 285 / 9.84 = 29 minutes.
- 4
Adjust for personal MET reality. Untrained: subtract 5-10% (less efficient). Trained: subtract 10-15% (more economical, lower MET at same pace).
Untrained cyclist: 29 × 0.95 = 28 min effective. Trained: 29 × 0.88 = 25 min.
- 5
Don't take the number literally as 'canceling' food. EPOC + post-exercise appetite typically replace 25-40% of expended calories. Use as a perspective tool.
29 min cycling 'burns' 285 kcal but adds ~70-115 kcal extra hunger across the day. Net deficit only if you don't compensate.
Worked example
75 kg person wants to know how long to walk to burn off a 600-kcal dinner
Food kcal
600 kcal
Activity
Walking moderate (3.5 MET)
Body mass
75 kg
minutes = 600 / (3.5 × 75 × 0.0175) minutes = 600 / 4.59 minutes = 130.7 → ~131 minutes
131 minutes (2h 11m) walking to nominally burn the dinner. Caveat: in practice, walking for 2 hours produces 200-300 kcal of additional hunger that you may eat back. Use this number to reframe portion choice ('this dinner = 2h walking'), not as a literal cancel button.
Common variations
Run the numbers next
- Cardio Calories Burned Calculator
Estimate exercise calorie burn from body weight, duration, MET intensity, and incline.
- Cardio Walking Calorie Calculator
Estimate calories burned from walking using speed, duration, body weight, and incline.
- Nutrition TDEE Calculator
Estimate your daily energy expenditure with Mifflin-St Jeor + activity factors.
Questions people ask next
How do you calculate how long to exercise to burn off food?
Use minutes_to_burn = food_kcal / (MET x mass_kg x 0.0175), where 0.0175 converts 1 kcal/kg/hr into per-minute terms. Look up the MET for your activity (walking 3.5, jogging 7.0, running 10 km/h 9.8, moderate cycling 7.5), use your body weight in kg, and the food's calorie count. For example, a 285 kcal slice of pizza for a 75 kg person cycling at 7.5 MET is 285 / (7.5 x 75 x 0.0175) = about 29 minutes.
What is a MET and where do the values come from?
A MET (Metabolic Equivalent of Task) is an activity-intensity multiplier where 1 MET equals resting energy expenditure, about 1 kcal/kg/hour or 3.5 ml O2/kg/min. Walking at 3.5 MET means 3.5 times resting. The MET values used here come from the Ainsworth 2011 Compendium of Physical Activities, which are population averages with roughly plus or minus 15% individual spread.
Does exercising really cancel out the calories I ate?
Not literally. This formula gives a theoretical gross expenditure, but EPOC and post-exercise appetite typically replace 25-40% of the calories you expend, so you only net a deficit if you do not eat them back. Treat the number as a perspective tool for portion choice (this dinner equals 2 hours of walking), not as a literal cancel button.
Should I trust my fitness tracker's calorie burn over this formula?
For food-equivalence reasoning, trust this MET-based estimate. Wearable trackers often inflate calorie burn by 15-30% (Shcherbina 2017). For fat-loss accounting, also consider net rather than gross calories: net = gross x (1 - 1/MET), so walking at 3.5 MET gives 262 kcal/hr gross but only about 187 kcal/hr net above your resting BMR.
Sources
- Ainsworth et al. (2011). 2011 Compendium of Physical Activities: a second update of codes and MET values. , Medicine & Science in Sports & Exercise — canonical MET reference
- Borsheim & Bahr (2003). Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. , Sports Medicine — EPOC quantification
- Shcherbina et al. (2017). Accuracy in wrist-worn, sensor-based measurements of heart rate and energy expenditure in a diverse cohort. , Journal of Personalized Medicine — wearable kcal accuracy
- USDA FoodData Central , USDA — authoritative US food kcal database