Less active (20 to 30 minutes two to four times a week): Body weight in pounds x 13.5 to 15 calories = daily calories
Light to moderately active (45 to 60 minutes a day of purposeful moderate intensity exercise, most days of the week): Body weight in pounds x 16 to 20 calories = daily calories
Very active (60 to 120 minutes or more 5 to 6 days a week): Body weight x 21 to 25 calories = daily calories.
Whether you maintain, gain, or lose weight is a matter of energy balance. To lose a pound, you must create a deficit of 3,500 calories--by eating less, moving more or preferably, a combination of the two. Slashing 500 calories a day to lose a pound per week is too much for most female runners, who end up consuming too few of the nutrients needed for good health and performance. Trimming 200 to 300 calories a day is more realistic.
Make Your Calories Count
You have to eat in a way that allows you to train well both physically and mentally, says Edison. This type of diet, often referred to as high-performance eating, prepares your body for exercise without loading it down with unnecessary calories.
High-performance eating leaves you physically and mentally prepared to exercise, and it's not just for elite athletes or those planning to run a marathon. It's a common misperception that high-performance eating leads to weight gain, but it won't if done properly.
It's crucial to get balance and variety from a wide selection of foods. Figuring out exact percentages of carbohydrate, protein and fat isn't necessary. In fact, even the U.S. Department of Agriculture has realized one-size-fits-all diets don't work. Its 2005 dietary guidelines (available at mypyramid.gov) include 12 versions of the food pyramid, each slightly different, depending on a person's age, sex and level of physical activity.
In general, you should aim to eat enough fruit, vegetable, protein and grain servings every day to fuel your active lifestyle. Female runners need at least two cups of fruit, three cups of vegetables, six ounces of grains (make at least three servings whole grains), three servings of dairy, six ounces of meat or the equivalent from beans/ eggs and soy foods, and a minimum of 25 to 30 grams of fat (five to six teaspoons) daily.
"Eating to fuel yourself adequately not only enhances your running performance," says Edison, "it's the best path to a leaner, stronger body."
At every meal, eat lean protein-rich foods. Besides being nutritional powerhouses, foods like eggs, fish, poultry, lean red meat, beans or soy and low-fat dairy help sustain a steady blood sugar level, which decreases the desire to snack every hour or two.
Also include healthy fats like avocados, nuts and nut butters, seeds and low-fat salad dressings as they help quell cravings that can spiral into binge eating. Eat fruits and vegetables daily to get the antioxidants you need to repair exercise-induced damage.
Dr. Barbara Rolls, a nutrition researcher at Pennsylvania State University and the author of The Volumetrics Eating Plan, found the nutrient density of the foods is key to feeling satisfied sooner. As a general guideline, the higher the moisture content of a given food, the lower its energy density.
In other words, you can eat more of it--a satisfying portion--for a very reasonable amount of calories. You'll also feel fuller for longer after consuming it. Rolls found if you begin a meal with either a salad or soup, you're more likely to consume fewer calories during the meal.