What is the most accurate formula for determining caloric balance?

The most accurate formula for determining caloric balance  Comparisons, analyzes and practical application of the known formulas for calculation of BMR

The human body is a complex biological system with a number of regulatory mechanisms. Unfortunately, however, sometimes these mechanisms, which have done us a great job in the process of our evolution as a species, give less positive results in our modern daily lives.

One of the mechanisms that often does not work as we would like is that of weight regulation. In the conditions of easily accessible huge amounts of food, our tendency to stock up for hungry days, accumulating fat in our bodies, sometimes plays a bad joke on us. It is when we find this out that the best time to think about the ways in which we can determine exactly how much energy we need to absorb through our food.

We have already written about the caloric balance and the caloric optimum. The purpose of this article is more modest – to supplement the previous one by presenting some more modern methods for their calculation and to consider their advantages and limitations.

Calorie balance

It is not difficult to define what a caloric balance is. Everyone is well aware of its connection with health and good physical shape. However, the difficulties begin when we need to determine exactly what our neutral calorie balance is.

Calorie balance is the amount of energy needed by the human body to maintain its normal functions.

Our body is a complex system with many built-in mechanisms for regulation. In the context of caloric balance, this means that it is not a fixed value, but a range. But for now, let’s disregard that fact. The basis for calculating the neutral caloric balance is the basal metabolic rate, which for short we will call BMR

Emergence of the first formulas for calculating BMR

The first serious research on the subject began in the early 20th century in the nutrition laboratory at the Carnegie Institution of Washington under the direction of Francis G. Benedict. Together with his colleague, J. Arthur Harris conducted a study among 136 men, 103 women and 94 newborns. In October 1918, the two published their results, based on which they determined the first formulas for calculating BMR depending on weight, sex, age and height:

• Men: BMR = 66.473 + (13.7516 x weight in kg) + (5.0033 x height in cm) – (6.7550 x age in years)
  
• Women: BMR = 655.095 + (9.5634 x weight in kg) + (1.8496 x height in cm) – (4.330 x age in years)

However, we still have one step left to calculate the neutral calorie balance. BMR only gives us the energy expenditure of the body at complete rest. Each of us moves, and even minimal physical activity, not including sports, increases energy expenditure by about 20%. In active athletes this percentage is even higher. Therefore, the result of the Harris-Benedict formula is multiplied by a coefficient of physical activity.

The most commonly used odds are the following:

• Little or no physical activity – 1.2
• Light exercise (1-3 days a week) – 1,375
• Moderate exercise (3-5 days a week) – 1.55
• Heavy exercise (6-7 days a week) – 1,725
• Very heavy exercises (twice a day) – 1.9

So, for example, if you get a BMR of 2000 calories and exercise 2-3 times a week, then your neutral calorie balance will be 2000 x 1.375 = 2750 calories.

In search of more accurate results

In the last decades of the 20th century, it became apparent that the original Harris-Benedict formula was yielding increasingly inaccurate results. The reasons are sought in the change of lifestyle and diet. In 1984, Alan M. Rosa and Harry M. Schizgal updated the Harris-Benedict formula on the basis of new data, changing the coefficients set in it:

• Men: BMR = 88,362 + (13,397 x weight in kg) + (4,799 x height in cm) – (5,677 x age in years)
• Women: BMR = 447,593 + (9,247 x weight in kg) + (3,098 x height in cm) – (4,330 x age in years)

This formula gives more accurate results and was the best means of calculating BMR until 1990, when a team led by M. Mifin and S. St. Jour published a new study in which they developed a different formula known as the Mifin-St. Journ formula. :

• Men: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + 5
• Women: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161

In it, the coefficients for weight, height and age in men and women are the same, and the difference in metabolism between the sexes is expressed in a common coefficient. Of the three formulas based on total weight, that of Mifin-St. Jury gives the most accurate results, but even with it the deviations are quite large.

Formulas for removing fat from total weight

However, as is well known, adipose tissue has a completely different metabolic activity than other tissues in the human body. Therefore, any formula that takes into account only the total weight will inevitably overestimate more and more BMR with increasing body fat percentage. To avoid this effect, two formulas have been developed that take into account active body weight, which is total weight minus body fat weight.

• The first is the Ketch-McArdle formula: BMR = 370 + (21.6 x active weight in kg)
• As its alternative, the Cunningham formula is used: BMR = 500 + (22 x active weight in kg)

For example, if you weigh 90 kilograms and 15% of them are fat, your active weight will be 76.5 kg, and BMR will be equal to 2022 kcal according to Catch-McArdle or 2183 kcal – according to Cunningham.

Comparison of the results of the different formulas

To compare with the results of formulas using total weight, let’s calculate them for a man with a height of 180 cm at the age of 30 years, whose weight and fat are the same as in the example with the two formulas with active weight.

• The original Harris-Benedict formula will give us a result of 2007 kcal;
• The revised one – 1988 kcal, and the one of Mifin-St.

Application of BMR calculation formulas

So far, we are well prepared to calculate our BMR in several different ways, multiply it by a coefficient of physical activity and get our neutral calorie balance. But what is the practical value of this little math exercise?

Unfortunately, the statistics show quite individual deviations. According to a study conducted among 150 people in Scotland, the basal metabolic rate varies from 1027 to 2499 kcal per day. The researchers calculated that 62.3% of this difference was due to the different percentage of active weight. The other factors were fat (6.7%), age (1.7%) and others. However, 26.7% remained unexplained differences, which could not be explained either by gender or the ratio of different tissues, or by the size of energy-intensive organs such as the brain.

This means that there may be a different base rate of metabolism, even when we compare two people of the same sex, the same age, the same height and even the same active mass. The first 5% of people consume 28-32% more energy than individuals in the last 5%. For example, one study showed that two individuals with an active weight of 43 kg had a baseline metabolic rate of 1075 kcal / day and 1790 kcal / day, respectively. This difference of 715 kcal / day is equivalent to a daily 10-kilometer run.

To make the “confusion” even greater, we must add that our individual BMR also depends on many other factors that remain unaccounted for in any of the formulas discussed above:

• stress level;

• ratio of macronutrients that we eat (because different foods have different thermal effects on our body);

• type of physical activity

• previous history of weight change (in people with a history of obesity, the formulas overestimate BMR, even if the latter have later normalized their weight).

Which formula to use and does this exercise make sense

There is a benefit to calculating BMR. It can give us a starting point and help us achieve our weight goals more accurately and with less difficulty.

The formula of Mifin-St. Jury gives the closest to the real results.

Once we know our result and have multiplied it by the coefficient of physical activity, we can orient our caloric intake by this neutral caloric balance, taking it into account our goals. This, of course, will not be true. As mentioned earlier, all the formulas cited in this article tend to overestimate BMR, and this applies more strongly to people with higher body fat percentages.

On the other hand, they are the ones who need the most accurate calculation of their neutral calorie balance in order to be able to progress on the one hand in terms of losing fat and weight, and on the other – not to starve and to get all the necessary nutrients. Therefore, my advice to such people is to adjust the result obtained by the formula by 5% down from the very beginning.

Verification in practice for the most accurate formula for determining caloric balance

The next step is a practical check based on the actually measured change in weight over a period of time. It is most convenient to do it once a month. According to a meta-analysis published by Dr. Max Vishnovsky in the American Journal Of Clinical Nutrition, with a calorie deficit and sufficient and equal intake of protein and carbohydrates, one kilogram of body weight lost is equivalent to a deficiency of 7709 calories. On this basis, we can now make an additional check of the neutral calorie balance calculated by the formula.

For example, if we lost two kilograms in a month with thirty days, it would mean that we were in a total caloric deficit of 15,418 calories or about 514 calories a day. If we eat an average of 2,500 calories a day at the same time, this gives us a neutral calorie balance of 3,014 calories. We already have a purely practical method for determining neutral balance, which does not depend on formulas.

It also has its limitations – published nutritional values ​​of food are not always accurate, measuring each bite is inconvenient and sometimes even impossible, roundness accumulates, the deficit per kilogram lost can vary depending on our diet and metabolism and so on. However, we already have two independent methods and can use one to check the results of the other.

Thus, with the accumulation of a little routine in accounting for daily caloric intake, we will have a tool to help us achieve our goals by telling us whether our chosen diet needs adjustments, and in what direction. and how big they must be.

The Most Accurate Formula for Determining Caloric Balance

Sources used  for the most accurate formula for determining caloric balance  :

1. The Harris-Benedict Studies of Human Basal Metabolism: History and Limitations, Frankenfield DC1, Muth ER, Rowe WA, J Am Diet Assoc. 1998 Apr;98(4):439-45.
2. Biometric study of human basal metabolism by j. arthur harris and francis g. benedict nutrition laboratory and station for experimental evolution, carnegie institution of washington
3. A biometric study of basal metabolism in man (1919); Harris, James Arthur; Benedict, Francis Gano; Washington Carnegie Institution of Washington
4. Roza, Allan M; Shizgal, Harry M (1984). “The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass”. The American Journal of Clinical Nutrition 40: 168–182.
5. Mifflin, MD; St Jeor, ST; Hill, LA; Scott, BJ; Daugherty, SA; Koh, YO (1990). “A new predictive equation for resting energy expenditure in healthy individuals”. The American journal of clinical nutrition 51 (2): 241–7
6. Speakman, John R.; Król, Elzbieta; Johnson, Maria S. (2004). “The Functional Significance of Individual Variation in Basal Metabolic Rate”. Physiological and Biochemical Zoology 77 (6): 900–915. doi:10.1086/427059. PMID 15674765.
7. McArdle, W (2006). Essentials of Exercise Physiology. Lippincott Williams & Wilkins. p. 266. ISBN 9780495014836.

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