Nutrition Calculation Information

Supporting Research & Explanatory Details

Fittur calculates daily nutrition targets (calories, carbs, protein, fat, and fiber) based on the Resting Daily Energy Expenditure (RDEE) and the Total Daily Energy Expenditure (TDEE) of each individual using body weight, body fat, activity/exercise level, and self-selected calorie deficit or calorie overload. The following research and explanations support the calculations used to generate the RDEE and TDEE as well as how those calories are divided between carbs, protein, and dietary fat. 

Predictive Equations For Estimating Resting Energy Expenditure

Comparison of Estimates of Resting Energy Expenditure

New Approaches to Body Composition Evaluation

The Role Of Macronutrient Content in the Diet For Weight Management

Effect of Macronutrient Composition On Short Term Food Intake and Weight Loss

Effects of Macronutrient Composition on Body Composition and Fat Distribution During Weight Maintenance and Weight Loss

Body Fat Mass and Macronutrient Intake in Relation to Circulating Soluble Leptin receptor, Free Leptin Index, Adiponectin, and Resistin Concentrations In Healthy Adults

Body Macronutrient Composition Is Predicted by Lipid and Not Protein Content of the Diet

Physical Activity Energy Expenditure in Successful Weight Loss Maintainers

The Effect of Exercise on Non-Exercise Physical Activity and Sedentary Behavior in Adults

A New Predictive Equation For Resting Energy Expenditure In Healthy Individuals

A Predictive Equation To Calculate Resting Metabolic Rate In Athletes

Comparison of Methods to Assess Energy Expenditure and Physical Activity in People With Spinal Cord Injuries

How Many Calories Do You Need?

Energy Expenditure Formulas: Basal Metabolic Rate and More, Wikipedia

Example Calculation of Nutrition Targets

The following example calculates the calories, carbs, protein, fat, fiber, additional calories from exercise, and the calorie deficit or calorie overload for a 150 pound person. The calculations for BMI, Military Body Fat Percent, Net Carbs, Pregnancy Calories, and Breast Feeding Calories follow.

Resting Daily Energy Expenditure Calculation (RDEE)

First, convert body weight from pounds to kilograms:

150 lbs / 2.2 = 68

Second, your app determines lean body mass by multiplying body weight by percent body fat:

68 kg. x 20% body fat = 13.6 kg of body fat

Next, subtract body fat weight from total body weight to determine lean body mass:

68 kg – 13.6 kg = 54.4 kg

Now multiply by 21.6 to get the Resting Daily Energy Expenditure (RDEE)

54.4 x 21.6 =  1,175 calories

Finally, calculate the RDEE by adding 370 calories:

1,175 calories + 370 calories = 1,545 calories RDEE

Protein Target Calculation

Establish the protein calories by multiplying body weight by the number of grams of protein per pound of body weight. If the subject is near 10% body fat then that number is 1.1 grams per pound:

150 lbs x 1.1 = 165 grams of protein per day

 The following table is for each five percent change in body fat.

15% body fat multiply your weight by 1.0

20% body fat multiply you weight by .95

25% body fat multiply your weight by .90

30% body fat multiply your weight by .85

over 35% body fat multiply your weight by .80

Since each gram of protein has four calories, multiply this number by four:

150g protein x 4 = 

600 protein calories per day

Dietary Fat Calculation

After calculating the protein target our 150 pound example with 945 calories remaining:

1,545 calories – 600 protein calories = 945 calories remaning

Assign between 20% and 25% of the remaining calories to the dietary fat target. The higher the body fat level, the closer the calculation assigns dietary fat at 25% of remaining calories. The lower the body fat, the closer the calculation assigns dietary fat at 20% of remaining calories. Over 30% body fat the calculation is set at 25% of remaining calories. Below 15% body fat the calculation is set at 20% of remaining calories. Between 15% and 30% body fat, the dietary fat target assign the percent of remaining calories on a sliding scale.  

945 calories x .25 =  236 dietary fat calories

Each fat gram has 9 calories, determine out how many grams of fat to eat by dividing by 9:

236 fat calories / 9 =  26 g of fat to eat

Carb Target Calculation

The remaining 709 calories are assigned as carb calories. Each each carb gram has 4 calories, calculate how many grams of carbs to eat by dividing by 4:

709 carb calories / 4 =  177 g carbs

Fiber Target Calculation

The fiber target can be adjusted in the app to fit any diet reccomendation. The default calculation is 20 grams of fiber per 1,000 calories

Exercise Calorie Calculation

To calculate the additional calories from exercise, multiply the amount of time the subject exercises by the MET value (metabolic equivalent of task). 

You can look up the MET value for your exercise or activity on this table. 

If you selected weight lifting as your exercise, then, multiply the time you lift weights in minutes by the MET value to get the number of calories you burn:

90 minutes x 6.0 = 540

Add the exercise calories to the total calories after the protein target is calculated. Exercise calories increase the carb and fat target, but the protein target doesn’t change with exercise.

Target Calculation Summary

The new targets for a 150 pound person with exercise added look like this:

Calories = 1,545 + 540 = 2,085

Carbs = 177g + 101g = 278g

Protein =  150g

Fat = 26 g + 15g = 41g

Calorie Deficit Calculation

The ideal calorie deficit is 20 to 30% fewer calories than you burn each day. Use the calorie dial to select the calorie deficit or overload, then either add or subtract the percent of calories adde or removed from the daily calorie intake. Here’s what the final targets look like for a 150 pound person in a 25% calorie deficit (calorie dial set at 75%):

Calories = 1,563

Carbs = 208 g

Protein = 150 g

Fat = 31 g

Military Body Fat Calculation

For males: % body fat = 86.010 x log10(abdomen – neck) – 70.041 x log10(height) + 36.76

For Females: % body fat = 163.205 x log10(waist + hip – neck) – 97.684 x log10(height) – 78.387

BMI Calculation

Imperial Measurement

 703 x weight (lbs) / [height (in)]2 

Metric Measurement

weight (kg) / [height (m)]2

Pregnancy Calculation

First Trimester: No additional calories added to diet

Second Trimester: 340 calories added if percent body fat is below 20%. For each additional percent body fat, 28.33 calories are added to the diet through 32% body fat. Above 32% body fat, no additional calories are added to the diet.

Third Trimester: 452 calories added if percent body fat is below 20%. For each additional percent body fat, 37.66 calories are added to the diet through 32% body fat. Above 32% body fat, no additional calories are added to the diet.

*The macro nutrients are calculated using the same formulas as indicted above.

Breast Feeding Calculation

During breast feeding, 500 additional calories are added to the diet if body fat percent is at 15% or lower. For each one percent increase in body fat from 16% to 40%, 20 fewer calories are added to the diet. Above 40% body fat 200 calories are added to the diet.  

*The macro nutrients are calculated using the same formulas as indicted above.

Net Carb Calculation

Total Carb Grams – Fiber Grams = Net Carb Grams