The amount of calories you need to consume will largely depend on your nutritional goals age weight activity level and gender. As a general rule of thumb a woman needs to eat about 1 500 to 2 500 calories per day. If her goal is weight loss she must consume fewer calories than someone who wants to get or maintain weight. Knowing your goals and what factors are involved will help you determine how many calories you should eat each day
Your body uses calories as energy for the day-to-day activities from working out to sit at your desk. Everything you do requires energy which is why a sedentary person may still require a significant number of calories. There are three factors that determine how calories are burned and how many you need to consume. They are your activity level your basal metabolic rate (BMR) and thermal effect of food.
To understand how much calorie consumption will vary depending on gender and weight consider this: On average a 30 year old woman who weighs 150 pounds needs to eat 2070 calories a day to maintain her weight. A woman of the same age who weighs 125 pounds should eat 1831 calories per day. A 30 year old man who weighs 150 pounds should eat 2256 calories per day.
BMR and thermal power
Your BMR is the amount of calories you burn at rest. It includes calories burned while sleeping breathing and pumping blood. It constitutes about 60 to 70 percent of your total calories burned. When dieting you should never consume fewer calories than your BMR. To calculate your BMR simply multiply your weight by 10. For a more accurate calculation use the Harris Benedict Equation. Men: BMR = 66 + (13. 7 x your weight in kilograms) + (5 x height in centimeters) – (6. 8 x age in years). For women :. BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4. 7 x age in years)
The thermal effect of food is the amount of calories you burn while eating. It accounts for about 10 percent of total calories burned.
You may be surprised to hear that someone who works out regularly but spend eight hours sitting behind a desk might not necessarily have a high activity level. On the other hand a nurse at the doctor who spend 12-hour days on his feet but never works actually require more calories than someone who frequents the gym. Your activity level includes all non-idle activity such as walking the dog gardening and exercising. The higher level of activity the more calories you need to consume. Your activity level can explain about 20 to 50 percent of your BMR. The Harris Benedict equation breaks activities into five categories:
Sedentary: BMR x 1.2
Gentle active: BMR x 1.375
Moderately active: BMR x 1. 55
Very active: BMR x 1.725
Additional active: BMR x 1.9
A healthy diet
The calories contained in food comes from proteins carbohydrates and fats. Your body uses all three to work. Fat helps the body absorb nutrients. Carbohydrates provide energy and protein helps build and repair muscles. The US Department of Agriculture (USDA) recommends that 45 to 65 percent of calories in a healthy diet should come from carbohydrates 10 to 35 percent from protein and 20 to 35 percent from fat.