Basal metabolic rate (BMR): Your BMR is the number of calories your body burns at complete rest. The energy needed to keep your heart beating, lungs breathing, your brain thinking, your temperature regulated, and just about every other conscious bodily function that’s running 24/7. It accounts for about 70% of the total calories you burn in a day. This is the part that is subject to being suppressed with certain metabolic diseases(like Hypothyroidism which can down regulate the BMR by 5-15%).

Non-exercise activity thermogenesis (NEAT): NEAT is the number of calories you burn from any physical activity that isn’t formal exercise (the calories you burn going about daily activities, basically). This includes your daily step count, fidgeting, standing vs. sitting throughout the day, etc. Depending on the lifestyle this can either make up the smallest chunk, or the second largest and is one of the best sections to focus on for burning more calories throughout the day (but more on that later)

Thermic effect of food (TEF): TEF is the number of calories you burn by digesting food. Yeah, you burn the 3rd most calories per day just simply digesting the food you eat, pretty cool huh? On average, TEF can account for about 10-15% of your TDEE, but it can vary depending on the types of food you eat. For instance, protein has the highest TEF of all foods at around 20-30%, meaning if you eat 100 calories of protein, you burn 20-30 calories just digesting it. Where fats for example have a TEF of 0-3%, meaning if you eat 100 calories of fat, you only burn about 0-3 calories digesting it.

Exercise activity thermogenesis (EAT): EAT is the number of calories you burn doing formal exercise. Shockingly, for most people, EAT is the smallest section and contributes about 5% to TDEE.