Food provides you with energy in the form of calories. Calories help your body perform basic functions, such as breathing, and also help fuel activity from mundane tasks to marathons. Too few calories may leave you short on energy, but too many can lead to weight gain. What constitutes a normal calorie intake depends on many factors.
Expert Recommendations
The 2010 USDA Dietary Guidelines outline specific recommendations for the range of calories you need depending on your age, activity level and gender. In general, children need more calories as they age and adults need fewer as they age. The recommendations for adults are based on a man who is 5 feet, 10 inches tall and weighs 154 lbs and on a woman who is 5 feet, 4 inches tall and 126 lbs. If you weigh more or less, you will need more or fewer calories accordingly to maintain your weight. Adult men ages 19 to 30 years need between 2,400 and 3,000 calories per day. Those ages 31 to 50 years may need as few as 2,200 calories per day, and those over 51 years old may need only 2,000 calories per day. Women need fewer calories because of their tendency to be smaller in size. Adult women ages 19 to 30 years need between 1,800 and 2,400 calories daily, and those between the ages of 31 and 50 years generally should not exceed 2,200 calories daily. Women over the age of 51 years may need as few as 1,600 calories. The more active you are, the higher your calorie intake within the given ranges.
Nutrition
Not only is the number of calories you consume important, but so is the quality of the calories you consume. Ideally, 85 to 100 percent of your calories should come from nutritious foods, such as lean proteins, whole grains, fresh fruits and vegetables, nuts, seeds and low-fat dairy. The Institute of Medicine recommends you get 45 to 65 percent of your calories from carbohydrates, 10 to 35 percent from proteins and 20 to 35 percent from fats.
Reality
According to the Centers for Disease Control and Prevention National Health and Nutrition Examination Survey, published using data from 1999 to 2000, men consume an average of 2,475 calories daily and women 1,833 calories daily. On average, Americans get 33 percent of their calories from fats, 15 percent from proteins and 52 percent from carbohydrates.
Minimums
Trimming your calorie intake can lead to weight loss. You have to eat fewer calories than you burn, about 500 per day, to lose 1 lb. per week. While it would seem that trimming calories to as low an intake as possible would yield the fastest, most efficient weight loss, this is definitely not the case. Women need at least 1,200 calories per day and men 1,500 calories per day to support health, nutritional needs and energy. Losing weight too quickly by starving may put your body into a preservation mode in which your metabolism comes to a standstill in order to prevent starvation.
References
- Centers for Disease Control and Prevention; National Health and Nutrition Examination Survey; Intake of Calories and Selected Nutrients for the United States Population, 1999-2000
- National Heart, Lung and Blood Institute: Balance Food and Activity
- U.S. Department of Agriculture: Dietary Guidelines for Americans; 2010
- Mayo Clinic; Metabolism and Weight Loss: How You Burn Calories; Oct. 6, 2009
- Institute of Medicine; Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids; Jan. 20, 2011
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