Weight Loss Formula for Caloric Needs

Learn how to calculate caloric intake to lose weight

calculate your caloric needs
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Do you know the weight loss formula that will help you slim down? If you're serious about losing weight you should be able to calculate caloric intake and calculate the energy deficit needed for weight loss. But don't worry, it's not as hard as it sounds. Just use these simple formulas to get the right numbers. 

The 2-Step Weight Loss Formula

How many calories should you eat to lose weight? There is no magic number that works for everyone.

Some people can lose weight eating around 1,200-1,500 calories per day. But you can also calculate your own personalized number using a two-step process.

First, you estimate you estimate your caloric needs. This is how many calories you should consume to maintain your weight. By using a simple formula called the Harris-Benedict principle, you get a good estimate of what your body needs to stay healthy.

Then, to lose weight, you'll need to cut calories from your diet, burn extra calories with exercise or combine both strategies (which is the method that most experts recommend).  This step is often called creating a calorie deficit.

Steps one and two are outlined below. Take a few minutes to follow the weight loss formula. It will become the foundation on which you build your healthy weight loss program.

How to Calculate Caloric Needs

Your basal metabolic rate (BMR) is the amount of energy your body needs to function at rest.

We use about 60% of the calories we consume each day for basic bodily functions such as breathing. Height, weight, age, and sex can influence your BMR.

Step one is to calculate your BMR with the following formula:

  • Adult Women:
    655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
  • Adult Men:
    66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)

Step two: is to multiply your BMR by an activity factor to determine your caloric needs. Each activity category listed below has a range. Choose a number based on where you fall in that range. 

  • If you are sedentary or mostly sedentary multiply your BMR by 1.0-1.39 
  • If you are lightly active (you do 30-60 minutes of easy physical activity each day), multiply your BMR by 1.4-1.59
  • If you are moderately active (you do 60 minutes of moderate physical activity each day) multiply your BMR by 1.6-1.89
  • If you are very active multiply your BMR by 1.9-2.5. Very active people do at least 60 minutes of moderate physical activity each day plus 60 minutes of vigorous activity or do at least 120 minutes of moderate activity each day.

The result of this formula will be a good estimate of the number of calories you can eat every day to maintain your current weight. In order to lose weight, you'll need to create a calorie deficit by taking in fewer calories than this result.


How to Create a Calorie Deficit

In order to lose weight, you must eat fewer calories than your body needs so that your body burns fat for fuel.  So how do you know how many calories to cut?  The number depends on how quickly you want to lose weight.

For every 3,500 calories you cut, you are likely to lose about one pound.  So, if you cut 500 calories per day, you should lose about one pound per week. You can also exercise to burn an extra 500 calories per day.  If you do both, you'll get results faster. 

Your weight loss will vary from week to week and at times you may even gain a little weight. Weight variations are a normal part of the weight loss process. The key is to stick to the program and maintain consistency. The long-term results are what matters.

healthy weight loss goal is to lose one to two pounds per week. Cutting too many calories and losing can cause your weight loss plan to backfire. For this reason, you shouldn't eat less than 1,200 daily calories without guidance from a registered dietitian or physician.

How to Cut Calories

To find out how you are spending your current calorie intake, keep a detailed food diary for at least one week.  With careful review, you will find ways to cut 250 - 500 calories per day. It may be as simple as switching to nonfat milk or skipping your afternoon soda habit.   Making little changes like these will really add up in the long run.

As you check the calorie content of the foods you record in your food diary, pay attention to serving sizes.  If you make sure to eat the right amount of food each time you sit down to a meal or eat a snack, you may be able to cut calories without giving up any of your favorite foods,

Burn Calories to Lose Weight

You can also become more active to create your calorie deficit. And hard sweaty exercise isn't required. Sometimes easy exercise for beginners is best. For example, a 180-pound person who walks at a brisk 3 mph will burn just over 250 calories in 45 minutes.

If you haven't exercised in a while, you should check with your doctor before starting a new fitness program. Then begin slowly and add activity as your fitness level improves.

Then, as your body size changes use the weight loss formula to calculate your BMR again. Then adjust your numbers as needed based on your new weight and your new goals.

*Edited by Malia Frey, Weight Loss Expert

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