Calorie Calculator II

How does this calorie calculator function?

This is a health tool based on the Katch-McArdle formula that calculates the daily calorie intake needs in order to either keep your current weight, lose or gain some weight (1,2 or 3 lbs/week or 0.5, 1 or 1.5 kg/ week).

This calorie calculator is organized in two tabs for the English and Metric measurement systems and you can use the one that is more convenient to you in order to input the weight, height and neck, waist and hip measurements. You will also be asked about your age and gender in order to be created a more personalized profile.

The result you will get contains the daily calorie requirements as well as some other indicators that you might find valuable in your weight assessment such as the body fat percentage, lean body weight, BMI & BMR value. 

The algorithm used is described in 3 stages:

1. First step: based on the data specified the calculator finds the body fat percentage and the other results related to body fat percentage.

2. Second step: it finds the fat free mass using the weight specified and the body fat percentage previously calculated. The formula for the fat free mass (FFM) is:

FFM= Weight in lbs – [Body Fat % * Weight in lbs]

3. Third step: Then it applies the Katch-McArdle formula:

Calorie needs= (21.6 * FFM) + 370

No matter which method used, together with the daily calorie needs estimations in order to maintain current weight, the form returns the daily calorie needs for a weight loss plan and for a gain weight plan with 1 or 2 lbs per week (or with the equivalent of 0.5 or 1 kg per week).

Example of a result

Let’s take for instance the case of a 30 year old female, weighing 164 lbs at a height of 5ft 4in, with a waist of 35in and neck dimension of 13in and hip of 47in. The result is:

- Based on Katch-McArdle formula, to maintain your weight you will need aprox. 1,494.87 calories/day or 6.25 kJ/day;

- To lose 1 lbs per week, you will need aprox. 994.87 calories/day or 4.16 kJ/day;

- To lose 2 lbs per week, you will need aprox. 494.87 calories/day or 2.07 kJ/day;

- To gain 1 lbs per week, you will need aprox. 1,994.87 calories/day or 8.35 kJ/day;

- To gain 2 lbs per week, you will need aprox. 2,494.87 calories/day or 10.44 kJ/day;

- Your Body Fat is 45.5%;

- Body Fat: 33.85 lbs;

- Lean Body Weight is: 40.54 lbs;

- Your Weight is: Overweight;

- Your BMI is: 28.2;

- Your BMR is: 1,520.8 calories/day;

- Minimum Calorie requirement is: 1,825 calories/day.

What if you want to lose weight?

In this case you should follow the appropriate part of the result as the form already subtracted from the BMR value obtained by Katch-McArdle formula either 500 calories/day for somebody who wants to lose 1 lb (0.5 kg equivalent) per week, or 1000 calories/day for somebody who wants to lose 2 lbs ( 1kg equivalent) per week.

However you should be careful not to go past these goals because these are designed to ensure that you maintain a healthy loss plan and that you don’t make any excesses that could affect your overall health.

Please note this should NOT be considered as a substitute for any medical professional advice or service as it is a rough estimation, while it is recommended to contact a nutritionist for a more personalized plan.

Why is knowing body fat important?

This is an important component of the total body mass alongside the lean body mass. Every person has a different amount of fat distributed similar. We already know that women tend to have fat distributed in the area of the hips and thighs while men seem to put on more on the abdomen.

Analyzing body fat rather than the whole body mass index can provide insight in one’s weight range as someone with a high BMI isn’t necessarily overweight unless their body fat is more predominant than the lean body mass (that comprises of muscles, bones, organs and skin).

References

1) Frankenfield D1, Roth-Yousey L, Compher C. (2005) Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc; 105(5):775-89.

2) Smith DA, Dollman J, Withers RT, Brinkman M, Keeves JP, Clark DG. (1985) Relationship between maximum aerobic power and resting metabolic rate in young adult women. J Appl Physiol; 82(1):156-63.