Basal metabolic rate or BMR, is the minimal calorie need required for a healthy sustenance in a resting individual.

BMR can be responsible for burning up to 70% of the total calories expended, but this figure varies due to different factors like gender, age, weight, body fat %, diet, external temperature, exercise and hormones.

Harris Benedict principle is a method used to determine basal metabolic rate (BMR) and daily calorie need depending on the factors like height, weight, age, and gender.

Katch & McArdle Formula takes in account of the body composition parameters- fat % and lean mass; hence is more accurate than a formula based on total body weight.

Physical activity level (PAL) is a factor that is formulated on the extent of activity a person endures in a day. This takes into consideration of the graded exercises as well as other activities a person undergoes as part of their daily job or distinctive chores.

Total daily energy expenditure (TDEE), also known as our "maintenance level“ is the total number of calories that our body expends in 24 hours, including all activities. It is the first step in designing a personal nutrition plan for an individual to estimate how many calories one should burn in a day.