How Many Calories Should a Woman Eat per Day to Lose Weight?

Whether you're paleo or vegan, following Atkins or Dukan, or eating like women in France, you'll probably lose weight if you follow the pre-set meal plans presented by these diets' advocates. The authors of these plans may go into detail about why their specific approach to eating is superior to others, but really, they just offer different ways to cut calories. When you burn more calories than you consume, weight loss occurs.

Every woman has different levels of success with various diet plans, not because one diet works better than another, but because every woman has different caloric needs that vary according to body size, activity level, age and genetics. For weight-loss success, estimate how much you personally should eat per day to lose weight. Then, apply that amount to any balanced diet and watch pounds drop away.

The Harris-Benedict equation helps you estimate your basal metabolic rate, or BMR, which is how many calories you need daily to maintain your weight independent of daily activity and exercise. Many online calculators use this equation to give you a quick answer, but you can put pencil to paper to figure it out on your own. Plug your numbers into the following: 655 + (4.35 x your weight in pounds) + (4.7 x your height in inches) - (4.7 x your age in years). For a 40-year old, 5-foot, 5-inch woman weighing 160 pounds, the result comes out to 1,468 calories, for example.

Next, account for any movement you do during the day. If you're pretty inactive and spend much of your time sitting, reading and watching television, multiply your basal metabolic rate, or BMR, by 1.4. If you have a job that requires mostly sitting, but you do make an effort to exercise about one hour most days, multiply your BMR by 1.5. If your day has you cleaning house and performing active chores as well as doing regular exercise, multiply the number by 1.6. For those who are active military, construction workers or a full-time athlete, multiply the BMR by 1.9.

The woman in the example burns daily calories in a range from 2,055 to 2,790, and where she falls in that range depends on her daily activity level.

The supplied calculations help you estimate how many calories you burn daily and how much you can eat to maintain your weight. If you want to lose weight, conventional advice is to trim 500 to 1,000 calories from what you burn daily. This size calorie deficit yields a manageable loss of 1 to 2 pounds per week, since one pound equals 3,500 calories. So, if you determine you burn 2,400 calories per day, you need between 1,400 and 1,900 calories per day to lose weight. Larger or more active women can eat more and still lose weight, while more petite women may need to restrict calories further to see results.

For some people, the 500 to 1,000 calorie deficit is just too aggressive. It requires portion sizes that are just too small, and it leaves you hungry and dissatisfied. A calorie deficit of 250 to 300 calories may be more sustainable, although you can expect to lose only 1/2 pound per week or so. Gradual weight loss does tend to be most sustainable in the long run, however.

Functional medicine specialist, Dr. Mark Hyman, contends that although all calories are technically processed into the same amount of energy, they're not equal when it comes to satiation and nutrient value. When reducing your calorie intake, cut back first on empty calories such as refined grains, soda, sweets and saturated fats. Focus instead on getting the calories you do eat from whole, unprocessed foods such as fresh vegetables and fruits, lean protein, whole grains, dairy and unsaturated fats. Foods with high levels of fiber and water or high-protein foods tend to be most satisfying and filling. Bakery products and higher fat foods are less likely to fill you up, but they usually contain large amounts of calories.

If you're like some women, the only way for you to achieve your weight-loss goal is to eat fewer than 1,200 calories per day, so it's probably time to reevaluate your goals. You'll likely lose valuable muscle mass, battle extreme hunger, have little energy for daily activity -- let alone exercise -- suffer nutrient deficiencies and slow your metabolism when you try to sustain a diet that's so low in calories.

Instead of trying to subsist on such a low number of calories, increase your daily calorie burn. Move more by taking the stairs and walking at lunch as well as by hitting the gym for 60 to 90 minutes on most days of the week. You'll be increasing your calorie deficit without depriving yourself.