Welcome to brain Stuff from how stuff works dot com where smart Happens. I am Marshall Brain with today's question, how many calories does a person need daily? The number of calories the body consumes in a day is different for every person. You may notice on the nutritional labels of the foods you buy that the percent daily values are based on a two thousand calorie diet. Two thousand calories is a rough average of what a person might eat in a day, but your particular body might need
more or less than two thousand calories. Height, weight, gender, age, muscle mass, and activity level all affect your caloric needs. There are three main factors involved in calculating how many calories your body needs in a day. First, there's your base al metabolic rate. Second there's your physical activity, and third there's the thermic value of food. Your basil metabolic rate, or BMR, is the amount of energy your body needs
to function at rest. This accounts for about sixty two seventy of the calories burned in a day, and it includes the energy required to keep the heart beating, the lungs breathing, the eyelids blinking, the body temperature stabilize the brain, thinking, and so on. In general, men have a higher BMR than women do. One of the most accurate methods of estimating your basil metabolic rate is the Harrass Benedict formula.
For example, for an adult male, you take sixty six plus your body weight and pounds times six point three plus your height niches times twelve point nine minus your age in years time six point eight, and that will give you your basel metabolic rate. The second factor in the equation, physical activity, consumes the next highest number of calories. Physical activity includes everything for making your bed in the morning to jogging, walking, lifting, bending, and just generally moving
around burns calories. But the number of calories you burn in any given activity depends on your body weight. There are many sites on the web that will help you to calculate the number of calories that you use in different activities. Finally, the thermic effect of food is the final addition to the number of calories your body burns. This is the amount of energy your body uses to digest the food you eat. It takes energy to break food down to its basic elements in order to be
used by your body. To calculate the number of calories you expend in this process, multiply the total number of calories you eat in a day by point one or ten percent. If you need some how determining how many calories you eat in a day, look for a free food diary site on the web. The total number of calories of body needs in a day is the sum of these three different calculations. Do you have any ideas
or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com and be sure to check out the brain stuff blog on the how stuff works dot com home page.