Can You Survive on 500 Calories a Day?

Thanks to your body's energy reserves, you can survive on 500 calories a day, but not indefinitely. And not without effect to your health and fitness. Healthy weight loss is achieved through modest calorie reduction.

Function

• A calorie is the unit of measurement used to quantify the energy potential of food.

Types of Calories

• Not only are calories important, but a balance of calories in your diet is critical, because not all calories are alike. Carbohydrates breakdown into glucose (the primary fuel of the body, and the brain's preferred type of fuel), calories from fat (chiefly used to power muscle activity), and protein calories (the brain's back-up fuel choice).

Misconceptions

• It is true that in order to lose weight, you have to burn more calories than you consume. But starving yourself is not a healthy way to achieve this. Your body doesn't need just energy for muscle movement. Seventy percent of your body's energy requirement goes to basal operations, such as digestion, circulation, respiration, and cardiac function.

Effects

• Starving your body of calories depresses your metabolism. This forces your body to draw on its fat stores to compensate for the shortfall, and also break down muscle for protein calories.

Solution

• Calculate your basal metabolic rate to ascertain your body's basic energy needs. (Ref. 2.) Your daily caloric intake should not fall below this.