Page 3 - Energy Needs

Calories and Nutrients

Everyone needs energy to live. Energy is supplied to the body in units called calories. Food is necessary because it contains calories, as well as nutrients. Nutrients are chemical substances in food that the body needs for functions like growth, tissue maintenance, and tissue repair. There are six essential nutrients: carbohydrates, protein, fat, vitamins, minerals, and water. Carbohydrates, protein, and fat contain calories and thus provide energy. Vitamins, minerals, and water do not contain calories. The following chart briefly describes each of the six essential nutrients.

Nutrient	Roles	Sources
Carbohydrates	body's preferred fuel (energy) source intestinal health waste elimination	plant foods, grains, and dairy products
Protein	build and maintain tissues growth immune function energy when carbohydrate is not available	animal products (meat, poultry, fish, dairy) plant products (nuts, legumes, grains)
Fat	energy normal growth and development carrier of certain vitamins component of cell membranes	many foods, plant and animal products
Vitamins	certain body functions, like metabolism	variety of foods abundant in fruits and vegetables
Minerals	used in many cellular and physiological functions	variety of foods
Water	medium for chemical reactions waste excretion temperature regulation	drinking water and other beverages, water found in foods such as fruits and vegetables

You can read more detailed information about the nutrients in these handouts: Macronutrients handout and Vitamins and Minerals handout.

The specific amounts of calories and nutrients you need depend upon your age and activity level. Use the MyPyramid Plan (energy calculator - located right upper side of page) to find how many calories (how much energy) you need each day to maintain your present weight. College age males typically need 2400-3200 calories and college age females usually need 1800-2400 calories.

Record your energy needs on your self-evaluation worksheet.

though calorie counting can be important when initially learning about weight management, it can become tedious and lessen the pleasure of eating.  Additionally, some individuals may become obsessive about counting calories and develop disordered eating habits.  When it comes to long term weight management, keep an awareness of your body's energy needs and the approximate calorie content of foods, but learn to employ other eating principles rather than rigorously recording calorie numbers.

Nutrient Density

It is important to eat mostly nutrient dense foods. Foods of high nutrient density provide high amounts of nutrients but low to moderate amounts of calories. Foods of low nutrient density provide high amounts of calories but few nutrients. Examples of high nutrient dense foods include fruits and vegetables, whole grains, low fat dairy products, and lean meats. Examples of low nutrient dense foods include alcohol, highly processed snacks (like chips and cookies), and soft drinks.

For persons needing to lose weight, slow, steady weight loss of 1-2 lbs. per week is recommended. Similarly, to gain weight, slow, steady gains are recommended. To lose weight, eat fewer calories than you expend, and to gain weight, eat more calories than you expend through activity.  The next section will include information on ways to reduce your calories. 

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