Total Daily Energy Expenditure, (TDEE) the total number of calories your body burns in 24 hours.
Basal Metabolic Rate (BMR) is the minimum number of calories your body requires to perform essential, life sustaining functions, while at rest.
Build Muscle Choose this option to put you in a 300 calorie Surplus.
Lose Body Fat Choose this option to put you in a 300 calorie Deficit.
Macro Breakdown, your macro breakdown from the calories generated.
For safety reasons, calories will never drop below 1300 for women or 1500 for men.