Understanding your personal caloric needs and the effect of physical activity on those needs is important, it can also be unnecessarily confusing. Basically, the number of calories you need to eat each day is derived from many factors including your age, weight, height, gender, lifestyle, and overall health and fitness. It is common sense that a physically active 6 feet tall, 20 year-old man or woman needs more calories than a less active, 5-foot, 75 year-old man or woman … but how does a person find out how many calories they need based on their lifestyle and metabolism? It’s really not that hard.

You’ve probably heard of BMR or basal metabolic rate. Your basal metabolic rate is the minimum number of calories you would  need to perform all bodily functions while sleeping for an entire day. Those functions include keeping the heart beating, respiration, digestion, creation of new blood cells, temperature maintenance and metabolic processes. It does not include physical activities, still these basic functions can require as much as 70 percent of the total calories burned in a single day for some individuals.  The first step for any individual who has a fitness goal to lose, maintain or gain weight is to determine the total number of calories that their body uses for basic functioning – their BMR-  and daily activities per day.

A common method for measuring daily calorie usage is the Harris-Benedict equation. It estimates your basal metabolic rate, which is then multiplied by your level of activity. The result is your recommended daily calorie intake.