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Speaker 1: Welcome to brain Stuff from how stuff works dot com

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Speaker 1: where smart Happens. I am Marshall Brain with today's question,

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Speaker 1: how many calories does a person need daily? The number

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Speaker 1: of calories the body consumes in a day is different

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Speaker 1: for every person. You may notice on the nutritional labels

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Speaker 1: of the foods you buy that the percent daily values

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Speaker 1: are based on a two thousand calorie diet. Two thousand

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Speaker 1: calories is a rough average of what a person might

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Speaker 1: eat in a day, but your particular body might need

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Speaker 1: more or less than two thousand calories. Height, weight, gender, age,

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Speaker 1: muscle mass, and activity level all affect your caloric needs.

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Speaker 1: There are three main factors involved in calculating how many

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Speaker 1: calories your body needs in a day. First, there's your

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Speaker 1: base al metabolic rate. Second there's your physical activity, and

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Speaker 1: third there's the thermic value of food. Your basil metabolic rate,

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Speaker 1: or BMR, is the amount of energy your body needs

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Speaker 1: to function at rest. This accounts for about sixty two

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Speaker 1: seventy of the calories burned in a day, and it

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Speaker 1: includes the energy required to keep the heart beating, the

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Speaker 1: lungs breathing, the eyelids blinking, the body temperature stabilize the brain, thinking,

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Speaker 1: and so on. In general, men have a higher BMR

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Speaker 1: than women do. One of the most accurate methods of

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Speaker 1: estimating your basil metabolic rate is the Harrass Benedict formula.

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Speaker 1: For example, for an adult male, you take sixty six

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Speaker 1: plus your body weight and pounds times six point three

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Speaker 1: plus your height niches times twelve point nine minus your

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Speaker 1: age in years time six point eight, and that will

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Speaker 1: give you your basel metabolic rate. The second factor in

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Speaker 1: the equation, physical activity, consumes the next highest number of calories.

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Speaker 1: Physical activity includes everything for making your bed in the

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Speaker 1: morning to jogging, walking, lifting, bending, and just generally moving

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Speaker 1: around burns calories. But the number of calories you burn

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Speaker 1: in any given activity depends on your body weight. There

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Speaker 1: are many sites on the web that will help you

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Speaker 1: to calculate the number of calories that you use in

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Speaker 1: different activities. Finally, the thermic effect of food is the

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Speaker 1: final addition to the number of calories your body burns.

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Speaker 1: This is the amount of energy your body uses to

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Speaker 1: digest the food you eat. It takes energy to break

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Speaker 1: food down to its basic elements in order to be

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Speaker 1: used by your body. To calculate the number of calories

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Speaker 1: you expend in this process, multiply the total number of

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Speaker 1: calories you eat in a day by point one or

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Speaker 1: ten percent. If you need some how determining how many

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Speaker 1: calories you eat in a day, look for a free

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Speaker 1: food diary site on the web. The total number of

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Speaker 1: calories of body needs in a day is the sum

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Speaker 1: of these three different calculations. Do you have any ideas

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Speaker 1: or suggestions for this podcast? If so, please send me

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Speaker 1: an email at podcast at how stuff works dot com.

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Speaker 1: For more on this and thousands of other topics, go

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Speaker 1: to how stuff works dot com and be sure to

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Speaker 1: check out the brain stuff blog on the how stuff

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Speaker 1: works dot com home page.