How Many Calories Do You Need?

Try this simple method for calculating caloric needs — and hitting your weight-loss goals

by: Carole Carson, from: AARP, Updated May 2011

If you want to lose weight (or simply maintain your weight), you’ll need to calculate how many calories you burn each day.

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There are several methods for arriving at this number. Some are quite complex and involve calculations that consider factors such as age, sex, height, weight and daily exercise. I find many of the formulas daunting. It’s safe to say that if I have a hard time figuring them out, I probably won’t lead others through the computations.

Subscribing to Einstein’s philosophy that everything should be as simple as possible (including the calculation of daily caloric expenditure), I recommend the Rosati Method. Dr. Robert Rosati heads the Rice Diet Program in Durham, N.C.

He came up with this approach because, he says, too often we focus on weight loss and do not give sufficient attention to weight maintenance.

"Most people now know that if you reduce the calories you ingest and increase the calories you expend, you will lose weight," he says. "The dilemma for most people is how to keep it off! At the Rice Diet Program we teach a dieta, which is the original Greek word for 'way of life.' Creating optimal health and actualizing our life's potential includes not only an organic, locally grown diet (mostly plants), and daily exercise, but introspective practices that inspire emotional and spiritual health. Healing at our roots is the only sustainable solution for achieving health for our bodies, minds, spirit, as well as our planet."

— Getty Images

Since Rosati's program teaches a way of living, a simple, easy-to-use method for calculating calories is essential.

Here's the formula. Assuming it takes 10 calories per pound to maintain your weight, take your weight and multiply it by 10. For example, if you weigh 150 pounds, then your caloric allowance is 1,500 calories (150 x 10 = 1,500). If you exercise, add 100 calories for every mile walked or other equivalent form of exercise performed.

Here's how this method works for me. I weigh 130 pounds, so I begin with a base of 1,300 calories. Today I walked four miles, so I can add 400 calories to that base for a total of 1,700. If I eat less than this amount, I will lose weight. If I eat more, I will gain. If I eat 1,700 calories, I will maintain my weight.

Besides walking, I occasionally engage in doubles tennis or yoga. In this case, I add 100 calories for every 30 minutes of exercise — the equivalent of walking one mile. This calculation is my own approximation and not part of Rosati's method; nonetheless, the resulting number is accurate enough to serve my purposes. If you want a more precise measure of calories for specific exercises, see this list.

You can also use the Rosati Method to calculate your daily caloric allowance to achieve your weight-loss goal. For example, suppose your desired weight is 140 pounds. Multiplying 140 by 10, your daily caloric allowance is 1,400 calories. If you walk one mile a day, the daily allowance is 1,500 calories. If you consume calories at this level or lower, over time you will reach your goal of 140 pounds.

I hope you find the Rosati Method simple to use and helpful in your fitness journey.

Carole Carson, author of From Fat to Fit: Turn Yourself into a Weapon of Mass Reduction, serves as the coach for the AARP Fat to Fit online community.