Calories are necessary parts of life. You get into trouble when you eat too many and gain weight. But not eating enough is also bad for you. Calories are energy and food provides the energy you need to function and perform. Activity level, age and current body weight all play a role in determining how many calories you need each day. Manipulating calories can help you lose, gain or maintain weight, and it only takes a few minutes to determine what you need on a daily basis.
Calculating Daily Intake
Step 1
Step on the scales. Wear as little as possible and weigh yourself in the morning. Record your weight, the date, time of day and clothes you are wearing.
Step 2
Use the following equation to determine your basal metabolic rate, or BMR. Your BMR is the number of calories you need to maintain your weight. For women: 655 + (4.35 x weight in lbs.) + (4.7 x height in inches) - (4.7 x age in years) = BMR. For men: 66 + (6.23 x weight in lbs.) + (12.7 x height in inches) - (6.8 x age in years) = BMR
For example, a 6-feet, 35-year-old man weighing 180 lbs. would need 1863.8 calories per day minimum. Record your BMR in your notebook.
Step 3
Use the Harris-Benedict equation to estimate caloric needs factoring in your activity level.
If you are sedentary, multiply BMR by 1.2; lightly active, by 1.375; moderately active, by 1.55; very active, by 1.725; extra active, by 1.9.
If the same man exercises five or more days per week he is considered very active and should multiply BMR by 1.725 for daily caloric need of 3215. Record your result in your notebook.
Step 4
Determine if you need to lose, gain or maintain your body weight. If you need to lose weight you want to reduce your caloric intake by 15 to 20 percent, according to the American College of Sports Medicine. If you wish to gain weight,increase it 15 to 20 percent.
Say the same man wishes to gain a little weight. He would then want to consume 3697 to 3858 calories per day until he reaches his new goal weight. Record your total daily caloric need based on whether you wish to lose or gain weight. Use the number from Step 3 if you wish to maintain your weight.
Tips and Warnings
- Weigh yourself each week at the same time and during similar circumstances to monitor body weight. Adjust your caloric intake as your body, age or activity level changes. Spread calories throughout the day into small meals, instead of two or three large meals. Record what you eat and the calories the food contained to monitor progress. Keeping in mind that you need to burn an extra 3500 calories in order to lose one pound of fat, aim to lose only 1 to 2 lbs. per week if your goal is weight loss. Increase activity level as well as adjusting diet if you want to lose weight.
- Do not cut too many calories from your day, even if you are trying to lose weight. Avoid over-estimating calories for lifestyle and exercise. Keep in mind that this equation is not appropriate for people that are very muscular or extremely overweight. Consider speaking with a dietitian if you fall into one of these categories. Do not go below 1800 and 1200 calories per day for men and women respectively, as this is the absolute minimum needed and is usually too low for most people.
Things You'll Need
- Body weight scale
- Paper
- Pen or pencil
- Calculator
References
- "Nancy Clark's Sports Nutrition Guidebook"; Nancy Clark, MS, RD; 2008
- BMI Calculator: BMR Formula
- BMI Calculator: Harris Benedict Equation
- BMI Calculator: Calorie Intake to Lose Weight
- "ACSM's Guidelines for Exercise Testing and Prescription"; American College of Sports Medicine; 2010
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