What’s the ideal number of calories for an adult woman?

“Thanks for the variety of information you provide in ETR.

“Please advise me – what’s the ideal number of calories for an adult woman to eat per day? Is there a range, given factors such as age?”


Dear Liz,

In order to determine how many calories you need, first you have to figure out your Basal Metabolic Rate (BMR). Your BMR tells you the number of calories you’d burn if you stayed in bed all day.

The most accurate way to determine your BMR is with breath gas analysis. Many health clinics and fitness studios offer this test for around $50. But even without it, you can get an estimate of your BMR by using the Harris-Benedict Equation (HBE). This formula estimates your BMR using your age, gender, height, and weight.

• For women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) minus (4.7 x age in years)

• For men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) minus (6.8 x age in years)

Once you’ve determined your BMR, you need to factor in your activity level to get your total daily energy expenditure – the number of calories you require each day to maintain your current weight:

1. Sedentary (little or no exercise) – BMR x 1.2
2. Lightly active (light exercise/sports 1-3 days/week) – BMR x 1.375
3. Moderately active (moderate exercise/sports 3-5 days/week) – BMR x 1.55
4. Very active (hard exercise/sports 6-7 days/week) – BMR x 1.725
5. Extra active (very hard exercise/sports & a physical job) – BMR x 1.9

Here, for example, is the calculation for a moderately active 35-year-old woman who weighs 120 pounds and is 5′4″ tall:

655 + (4.35 x 120) + (4.7 x 64) minus (4.7 x 35) = a BMR of 1,313.3

1,313.3 x 1.55 = 2,036 calories per day

It’s important to note that the Harris-Benedict Equation will be accurate for most people, but it does not account for lean body mass. (Remember, leaner bodies need more calories than less lean ones.) Therefore, it will underestimate the calories needed by those who are very muscular and overestimate the calories needed by those who are very fat.

A few final pointers…

Your BMR decreases as you age. This doesn’t mean that you should deprive yourself of food. In fact, food deprivation will reduce your metabolism and foil your intentions. Instead, get most of your calories from:

1. Fiber-Rich Foods. Organic veggies and low-sugar fruits that are packed with fiber require more “processing” by the body, which means more calories are burned during digestion.

2. Metabolic Power Ingredients. Clean proteins and healthy fats are thermogenic (fat-burning) foods that power up the metabolism.

You can also improve your BMR with regular, vigorous exercise and weight training to maintain that lean, calorie-burning muscle mass.

– Kelley Herring

[Ed. Note: Have a question for an ETR expert? Send it to AskETR@ETRFeedback.com.]

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