The recommended amount of calories per day depends on your activity level, age, body frame, gender, metabolism and weight. Calories are measurements of energy that come from food. Eating too few calories causes weight loss, but you're jeopardizing your life when you have run out of body fat to fuel your body. "Total starvation causes death in eight to 12 weeks," according to The Merck Manual of Medical Information.
Factors
Individuals' activity level, age and gender is so important that the recommended amount of calories per day "varies markedly" from approximately 1,000 to more than 4,000, according to The Merck Manual. The encyclopedia estimates that the average inactive woman, senior citizen and young child need 1,600 calories daily. The average active woman, inactive man, preteen boy, and preteen and adolescent girl need about 2,000. The average adolescent boy and active man need about 2,400.
Weight
The Merck Manual lists average recommended amount of calories per day, but "An Invitation to Health" detailed the importance of weight and activity level. The college textbook estimated that a 154-lb. woman needs 2,400 calories daily if she exercises about 60 minutes daily, 2,150 if she exercises 30 minutes daily and 1,850 if she doesn't exercise. A 154-lb. man with the same activity levels needs 2,900, 2,600 and 2,200 calories, respectively. A 110-lb. woman with the same activity levels needs 1,850, 1,650 and 1,400 calories, respectively.
Metabolism
You need more calories if you exercise, but your chances of maintaining a healthy weight are better if you, for example, consume 2,500 calories daily and burn 500 calories daily exercising rather than consuming 2,000 calories and burning zero calories. That is because your metabolism becomes faster when you exercise regularly. You lose fat and muscle when you diet. You lose fat and build muscle when you exercise. Burning calories is easier when you have more muscles. Increasing your metabolism after a diet is difficult.
Warning
Losing weight by dramatically decreasing your calorie intake can be dangerous. In fact, "rapid weight loss is linked with increased mortality," according to "An Invitation to Health." Very-low calorie diets reduce fat and muscle. The heart is a muscle, and it can become so weak when it isn't nourished by food that it might have problems pumping blood. Very-low calorie diets can also cause blood pressure to fall sharply, abdominal pain, dizziness, fatigue, hair loss, light-headedness and nausea.
Theories
You don't gain weight by eating more calories than you need, according to the creators of two of the most prominent diets. Dr. Dean Ornish wrote in "Dr. Dean Ornish's Program for Reversing Heart Disease" that you gain weight when you eat too many fatty foods, particularly foods with a lot of saturated fat. The late Dr. Robert Atkins wrote in "Dr. Atkins' New Diet Revolution" that you gain weight when you eat too many carbohydrates and neither calories nor fatty foods cause body fat.
References
- The Merck Manual of Medical Information; 1999
- "An Invitation to Health"; Dianne Hales; 2003
- "The Complete Guide To Walking"; Mark Fenton; 2001
- "Dr. Dean Ornish's Program For Reversing Heart Disease"; Dr. Dean Ornish; 1996
- "Dr. Atkins' New Diet Revolution"; Dr. Robert Atkins; 2002
Member Comments