A healthy diet is one with enough calories to meet your daily energy needs, and a balanced intake of fat, carbs and protein. You need to accumulate a negative energy balance to lose weight. This simply means that you need to expend more calories through daily activity than you consume through food. Although you need to cut a certain amount of calories to lose weight, the percentage of calories from each of the three macronutrients should remain the same. The U.S. Department of Agriculture provides daily calorie estimates for women, but you can also calculate your own caloric needs.
The USDA estimates for a moderately active woman between the ages of 19 and 30 are about 2,000 to 2,200 calories each day. A sedentary woman of the same age requires 1,800 to 2,000 calories and an active 19- to 30-year-old needs about 2,400 calories. A moderately active woman between 31 and 50 needs 2,000 calories a day, while sedentary and active women of the same age need about 1,800 and 2,200 calories a day. Moderately active women over 50 need about 1,800 calories each day, while sedentary and active women over 50 need about 1,600 and 2,100 calories each day, respectively.
For more accurate results, you can calculate your own caloric needs based on your basal metabolic rate and typical exercise habits. Calculate your BMR by multiplying your weight in pounds by the number 4.35, your height in inches by the number 4.7 and your age in years by the number 4.7. Add the first two calculations together, and then subtract the third. Add this result to the number 655 to find your BMR. You can then determine your total caloric needs by accounting for your daily activity level. Multiply your BMR by the number 1.2 if you are sedentary, 1.375 if lightly active, 1.55 if moderately active, 1.725 if very active and 1.9 if you are extra active.
To lose body fat, you need to a negative energy balance. You can lose about 1 pound of body fat each week if you cut 500 calories from your diet each day. While your weight-loss goals may be more ambitious, gradual weight-loss programs are healthier and can prevent losses in muscle rather than fat, nutrient deficiency, dehydration and damage to vital organs. To determine the number of calories you need each day to lose 1 pound each week, simply estimate or calculate your caloric needs and then subtract 500.
Regardless of total caloric intake, you need the same relative percentage of fat, carbs and protein. The Food and Nutrition Board of the Institute of Medicine maintains acceptable macronutrient distribution ranges for a healthy diet for women of all ages. According to the IOM, adult women need to consume 20 to 35 percent of their calories from fat, 45 to 65 percent from carbohydrates and 10 to 35 percent from protein. If you are a moderately active woman between 19 and 30 and you want to lose 1 pound each week, you would then need about 480 calories from fat each day, 800 from carbs and 320 from protein.
- Essentials of Strength Training and Conditioning; Thomas Baechle and Roger Earle
- U.S. Department of Agriculture: Dietary Guidelines for Americans 2010
- BMI Calculator: BMR Formula
- BMI Calculator: Harris Benedict Equation
- Institute of Medicine: Dietary Reference Intakes: Macronutrients
- woman running on the seashore image by Leonid Tarassishin from Fotolia.com
This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.