Do you fear that your recommended calorie range is too high? Are you consistently eating fewer calories than your SparkPeople plan advises? Have you found yourself wondering, “How exactly do they determine the number of calories that is right for me?”

While determining how many calories each individual should eat for successful and healthy weight loss isn’t exactly rocket science, it can be pretty darn confusing. So for those who want a deeper understanding, “Calorie Calculations 101” explains the formulas, mathematics, and general nuts and bolts, in 10 easy steps.

Case Study
To show how these calculations work, we will use “Sparkie” as an example. Here are Sparkie’s important stats that will affect her weight loss and calorie needs:
• Age: 35
• Gender: Female
• Height: 5 feet, 7 inches (67 inches)
• Current weight: 180 pounds
• Goal weight: 160 pounds
• Fitness plan: Three 30-minutes cardio sessions per week
See formula & example to the right -->

 Because these formulas use height in both centimeters and meters, here’s how to calculate it: Multiply height in inches by 2.54 to convert inches to centimeters. So, Sparkie’s height conversion would look like: 67 x 2.54 = 170 centimeters, or 1.7 meters Because these formulas use weight in kilograms, here’s how to calculate it: Divide weight in pounds by 2.2 to convert pounds into kilograms. So, Sparkie’s weight conversion looks like this: 180 ÷ 2.2 = 82 kilograms

# Step #1: Determine Your Body Mass Index

Body Mass Index (BMI) is a quick and easy formula for determining if your weight is appropriate for your height. It has recently been used to quantify an individual's obesity level. You can use this tool to determine if you need to lose weight in the first place. To the right is the general formula, using Sparkie as an example.

See formula & example to the right -->

According to the USDA guidelines, a BMI less than 25 is healthy, from 25 to 29.9 is classified as overweight and anything over 30 is considered obese.

Keep in mind that BMI is just one part of your health profile. It measures a general relationship between weight and height, but does not distinguish between fat (which doesn’t weigh much) and muscle (which weighs a lot). A thin but sedentary person could have a healthy BMI, but be flabby and out of shape, for example. Finally, BMI is not considered reliable for everyone, including children, pregnant women, body builders, and the frail elderly. Read SparkPeople’s Fitness Reference Guide: Body Composition for more information about BMI.

 BMI = weight (in kilograms) divided by height squared (in meters). Sparkie’s BMI = 82 kilograms ÷ (1.7 meters x 1.7 meters) = 28.

# Step #2: Set Your Weight Loss Goal

Research shows that slow, gradual weight loss is not only healthier, but that individuals who lose weight slowly tend to keep the weight off. Many fad diets promise excessive amounts of weight loss in a short amount of time, which can be dangerous and impermanent. Therefore, SparkPeople will NOT let people set a weight loss goal that is too aggressive. While the weight may come off slowly, you will have a better chance of maintaining your weight loss over time.

If you set an aggressive weight loss goal (2 pounds per week or more), your calorie range will be lower. If you set a gradual weight loss goal (1 pound per week or less), your calorie range will be higher.

See formula & example to the right -->

 Because Sparkie wants to lose 20 pounds total, it could take her about 10 weeks to get there. To be on the safe side, she sets a target date of 20 weeks (5 months) in the future, which means she’ll lose about one pound per week on her diet plan, plus she’ll get to eat more.

# Step #3: Plan for Fitness

During the set-up phase of the SparkPeople program, enter how much exercise you plan on doing. SparkPeople encourages its members to complete at least 3 days of cardio/aerobic exercise and 2 days of strength training each week. Based on your selections, we are able to determine how many calories you are burning each week through your fitness and exercise alone.

Being honest and accurate here is important. An individual who exercises a lot needs more calories than a person who doesn’t exercise at all. If you do exercise, but did not account for it during set-up, your calorie recommendation could be too low; this could slow down or completely prevent weight loss. Similarly, if you do not exercise, but said that you do, your calorie recommendations will be too high, also making it harder for you to lose weight.

See formula & example to the right -->

 Sparkie walks for 30 minutes, 3 days per week and entered this during set-up. At 180 pounds, she burns 670 calories weekly and her fitness plan reflects this with a weekly goal, advising her to burn 670 calories through cardio.

# Step #4: Meeting Your Basal Metabolic Needs

Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic, everyday functions like circulating blood, digesting food, and breathing. SparkPeople uses the Harris Benedict Formula to calculate your BMR, which differs between men and women.

See formula & example to the right -->

This number reflects how much Sparkie would need to consume, just to live—even if she did nothing but lay in bed all day. It will come into play in the next equation.

 Female BMR = 655 + (9.6 x weight in kg.) + (1.8 x height in cm.) – (4.7 x age in years) Male BMR = 66 + (13.7 x weight in kg) + (5 x height in cm.) - (6.8 x age in years) Sparkie’s BMR = 655 + (9.6 x 82 kg.) + (1.8 x 170 cm) – (4.7 x 35 years) = 1,583 calories

# Step #5: Sedentary Lifestyle Assumption

SparkPeople makes the assumption that everyone is fairly sedentary throughout most of the day, except for the planned fitness activities they do. This sedentary lifestyle includes light walking on the job, light housekeeping, deskwork, running errands, etc. To determine the additional calorie needs of a relatively sedentary lifestyle, multiple your BMR by 1.2 to get the number of calories you need for both basal metabolic functions and light activity.

See formula & example to the right -->

 Sedentary lifestyle needs: BMR x 1.2 Sparkie’s sedentary lifestyle needs: 1,583 calories x 1.2 = 1,900 calories.

# Step #6: Total Your Daily Calorie Needs

However, if you are exercising (Step #3), your body needs even more calories. To account for these calories, first divide your weekly calories burned goal (Sparkie’s is 670, listed in Step #3) by 7, which gives you the average number of calories you burn through exercise each day.

These fitness calories must be added to get your total daily calorie needs. So, add Sedentary Lifestyle Calories (from Step #5) + Fitness Calories.

She can eat this much daily and maintain her weight, but in order to lose weight, she needs to eat less than this. That’s where Step #7 comes in.

See formula & example to the right -->

 Sparkie’s daily calorie burn = 670 calories weekly ÷ 7 days = 96 additional calories per day. Sparkie: 1900 sedentary calories + 96 fitness calories = 1,996 total calories daily.

# Step #7: Account for Rate of Weight Loss

One pound of body fat equals 3,500 calories. Therefore, to drop 1 pound per week, you must create a deficit of 3,500 calories over the course of seven days, which equals 500 calories per day. To lose 2 pounds per week (3,500 calories x 2 pounds = 7,000 calories), you must cut 1,000 calories daily.

So by subtracting your weight loss rate (for example, 1 pound or 2 pounds weekly) from your Total Daily Calories (Step #6), you will create an appropriate caloric deficit in your body, and achieving your desired weight loss. There is no reason to cut additional calories, since this has already been included in the formula.

See formula & example to the right -->

 Total Calorie Needs – weight loss rate (in calories per day) = Your Calorie Goal for Weight Loss Since Sparkie wants to lose 1 pound per week, she needs to cut 500 calories per day. So, Sparkie's weight loss calorie target (1,996 calories – 500 calories) is 1,496 calories per day.

# Step #8: The SparkPeople Calorie Range

SparkPeople comes up with your individual calorie range by subtracting 250 calories from your weight loss calorie goal (Step #7) for the low end of the range, and adding an additional 100 calories to your weight loss calorie goal for the upper end of the range.

Once again, there is no reason to eat fewer calories than SparkPeople recommends, since this has already been done by the SparkPeople formula.

See formula & example to the right -->

 Weight Loss Calorie Goal – 250 calories = Lower end of calorie range Weight Loss Calorie Goal + 100 calories = Upper end of calorie range So the lowest amount of calories Sparkie should eat for weight loss is (1,496 calories - 250 calories) 1,246 calories daily. The highest amount of calories Sparkie can eat and still lose weight at a rate of one pound per week is (1,496 calories + 100 calories) 1,596. Sparkie’s weight loss calories range from 1,246 to 1,596 daily.

# Step #9: Rounding the Numbers

To make life easier, SparkPeople then rounds these numbers up to the nearest 10.

See formula & example to the right -->

# Step #10: For Your Health and Safety

The SparkPeople program will NOT allow any female to eat less than 1,200 calories daily or any male to eat less than 1,500 calories daily.

When calories drop too low (usually below 1,200 calories for women and 1,500 calories for men), your body’s protection mechanism switches on because the body thinks it is starving. In order to conserve energy, the body lowers your metabolism and you will not burn calories as quickly. This results in a slower weight loss rate, or sometimes prohibits any weight loss from occurring.

At SparkPeople we call this “Starvation Mode”. When your caloric intake falls below these levels, it is also extremely difficult to obtain all the nutrients that your body needs for health and survival. These very low calorie intakes can also lead to other health problems such as eating disorders, gout, gallstones, and heart complications.

 Sparkie’s 1,246 calories round up to 1,250 and her 1,596 calories round up to 1,600. On her Nutrition Tracker, Sparkie will see a weight loss range of 1250 to 1600 calories.