11/20/2025
Think of calories like energy money.
$
You spend it, save it, and sometimes overspend it and that balance determines whether your body gains, loses, or maintains weight.
If you want to lose fat, build muscle, or simply understand your metabolism... it all starts with calories in vs calories out.
This balance is called your Total Daily Energy
Expenditure (TDEE)
Basically how many calories your body burns in a day. It's made up of:
BMR (Basal Metabolic Rate) - ~60-70%
The energy your body uses just to stay alive, breathing, repairing cells, keeping your heart and brain working, etc.
•I TEF (Thermic Effect of Food) - ~10%
The calories burned digesting and processing food.
Protein actually takes the most energy to digest (20-30%), carbs a bit less (5-10%), and fats the least (0-3%).
NEAT (Non-Exercise Activity
Thermogenesis) - ~15-30%
All your non-gym movement: walking, cleaning, standing, fidgeting it all adds up.
EAT (Exercise Activity Thermogenesis) -
~5-10%
The calories burned through intentional workouts or lifting, cardio, sports, etc.
Depends on your effort, duration, and body size.
Calories In = what you eat & drink.
Calories Out = what your body burns.
Deficit (In < Out): you lose weight, your body uses stored fat for energy.
Surplus (In > Out): you gain weight, ideally muscle if you're training smart.
Maintenance (In = Out): your weight stays
stable.
Remember, hormones, sleep, stress, and digestion all affect how efficiently your body uses energy.
That's why two people can eat the same meal and get totally different results.
