Calculate your resting metabolic rate with an online RMR or BMR calculator
Measure your resting metabolic rate with indirect calorimetry at a clinic or fitness lab
Track your body weight, calorie intake, and activity level over time
Monitor changes in weight when eating a consistent number of calories
Review your body composition with a DEXA scan, bioelectrical impedance, or skinfold testing
Check your thyroid function with blood tests such as TSH, free T4, and free T3
Ask a healthcare professional about symptoms that may suggest a slow or fast metabolism
Compare your energy levels, appetite, and temperature sensitivity over time
Use wearable devices to estimate calorie burn during daily activity and exercise
Keep a food and activity log for at least 1 to 2 weeks to assess patterns