Caloric Needs for Individuals Based on Weight
1. Introduction to Caloric Needs for Individuals Based on Weight
Caloric needs pertain to the total energy requirements of any individual, which depend on various factors like age, sex, activity, and weight, among others. These needs are expressed in the number of calories to be obtained from the diet in a day. Energy expenditure occurs continuously even during sleep, in the form of basal metabolism (resting energy expenditure), and this can conveniently be expressed in calories.
Caloric needs include both the amount of energy to sustain metabolism and the amount needed for activities. The need for energy is affordable because food is readily available for the whole world population, and there is a constant striving for the ideal body weight. In this environment, daily energy requirements have been emphasized. This has led to a considerable interest in the caloric content of foods, and elaborate food tables allow frequent, though often meaningless, calculations of caloric intake.
However, the result of such calculations depends on the degree of chemical analysis, interpretation, and assumption made. There are almost no food tables on caloric needs, which are so significant for homoeopathic optimization of health, freedom from disease, and mental stress combined with maximal performance in sports or work.
The ideal body weight for both women and men has been calculated with demographic, anthropometric, and physiological considerations in mind, scaled to centimetres in height. These considerations allow the calculation of estimated body weights in adults best suited for the average woman and man living in developed countries.
The original formulas have been further modified. However, these body weight parameters may no longer be valid in modern society, with a high level of civilization forcing generations to earn their living increasingly by using transport and machines, sitting “behind the desk” rather than performing heavy physical activities.
Hence, weight parameters now must be calculated differently. There is a remarkably good correlation between height and weight in children with age and height. In the adult population overweight and obesity predominates. In parallel, weight for each age group has multiplied, same as in the height parameter. Such factors can be saved as weights that best fit the modern population living in developed countries.
Estimations of caloric needs were derived from physiologically plausible atmospheric gas exchange models primarily describing two doses to yield free movement and physical exercise. Such parametrized models reflect natural environmental conditions, body composition, and metabolism, resulting physiological parameters and performances like minute ventilation volume, respiratory quotient, and energy expenditure, which influence physiology in sport.
Combining these equations stomatognathic and respiratory work counts for sports ranging from aerial to purely terrestrial, with “earth and surface compliance” providing additional physiological explanations. Iterating such modeling with a goal of maximally precise physiological profile at its best has been employed to design the most demanding sports like formula-1 and altitude climbing. In astronomy, such mathematical and numerical methods were successfully employed to calculate trajectories of interplanetary spacecraft with gravitational assistance of planets.
1.1. Importance of Understanding Caloric Needs
An individual’s caloric intake and expenditure are essential for maintaining a healthy weight. It is possible to lose weight by taking in fewer calories than are burned, and it is possible to gain weight by taking in more calories than are burned. However, it is necessary to know how many calories are needed each day to make an accurate determination of how many to cut or add. This calculation will depend on a number of factors, including current weight, gender, height, age, and amount of activity in a day.
Caloric needs can be determined by beginning with basal metabolic rate (BMR), which is the rate of energy expenditure while at rest in a neutrally temperate environment. BMR is the energy needed for cardiac function, respiratory function, thermoregulation, nerve conduction, and tissue synthesis turnover, among other processes.
To calculate BMR, the Harris-Benedict equations can be implemented. The second component of energy expenditure is the thermic effect of food (TEF), which is the increase in energy expenditure above the BMR due to the cost of processing food for storage and use. TEF represents about 5 to 10% of total energy expenditure (TDEE). The third component of energy expenditure is activity thermogenesis, which is the energy expenditure beyond BMR in physical activity and other activities of daily living.
Total daily energy expenditure (TDEE) can be determined by summing all components of energy expenditure. Weight gain or loss is simply a result of energy imbalance between intake and expenditure. The recommended amount of caloric restriction for gradual weight loss is 500 to 1000 kcal/day, which results in a weight loss of 1 to 2 pounds/week. However, the energy intake restrictions should not drop below a certain limit, like 1200 kcal/day for women and 1500 kcal/day for men, or the diet will be nutritionally inadequate.
2. Factors Affecting Caloric Requirements
The number of calories the body burns in a day can be influenced by multiple factors. In other words, individual caloric needs depend on many different aspects of a person. Some factors have a greater effect on personal caloric needs than others. The primary determinant of the number of calories a body burns in a single day is its weight. Simply put, larger bodies tend to burn more calories because they require more energy to carry out basic bodily functions and activities. While this does not mean the same number of calories burn for any two individuals, it underscores the influence weight has in determining caloric needs.
To illustrate, two people might express concern over how much they eat in a day. They both exercise for an hour each morning and do little else physically. One, however, weighs in at 130 pounds, whereas the other weighs 220 pounds. Although the former and the latter both engage in the same activities and consume the same number of calories daily, the caloric balance at the end of the day is different. The body weighing 130 pounds burns approximately 1,800 calories in a day.
The body weighing 220 pounds burns approximately 2,800 calories in a day. That translates to a difference of about 1,000. No matter how many calories each consumes, the body at 220 pounds will undoubtedly accrue more reserves as unburned energy. As a result, they will gain weight over time, unless lifestyle or diet changes are made.
2.1. Weight
Caloric needs, defined in terms of food energy, vary from individual to individual and must be carefully assessed in order to formulate a nutritious regime. The most important determinants of caloric requirements are the weight of an individual and the degree of “activity” performed by him/her.
A six-foot-tall man of 200 pounds, for example, is expected to eat more than a five-foot woman of 100 pounds, and a person engaged in heavy muscular work is expected to eat more than a sedentary individual of similar stature. A third factor affecting nourishment is the previous intake of food, i.e., the diet he/she was on prior to assessing further needs.
After weight, the most important consideration is the previous diet, as many people may have their metabolic rates altered by prolonged intake of caloric surplus or deficit over weeks and months of time.
Regardless of height, frame, or activity, such individuals may require more or less calories than predicted by the weight alone having fattened or slimmed down in the period preceding such measurements. The assessment of this factor may be attempted by inspecting a chain of previous diets for their adequacy or by determining the BMR 1.
3. Calculating Basal Metabolic Rate (BMR)
If an estimate of caloric needs is desired, the first step is calculating basal metabolic rate (BMR). This is the number of calories needed at rest; it can be thought of as the amount of energy required to keep the lungs breathing, heart pumping, and liver performing its functions. Numerous equations may be used to estimate BMR, but one of the best known and most widely used is the formula by Harris and Benedict 2. Separate equations exist for men and women.
The Revised Harris-Benedict Equations are:
For Men: BMR = (13.751 x wt in kg) + (5.0033 x ht in cm) – (6.755 x age in years) + 66.473
For Women: BMR = (9.5634 x wt in kg) + (1.850 x ht in cm) – (4.676 x age in years) + 655.0955
BMR decreases with increasing age. The correlation coefficient squared (r2) between calculated and measured BMR is <0.75 for all formulae. Comparison of the basal metabolic rate values obtained by using the Harris and Benedict formula with measured values demonstrated that 42.6% of the subjects were more than 10% higher than the measured values.
Therefore, if weight is the only variable known, BMR can be roughly estimated as 22.5 kcal/kg body weight/day for individuals aged 30 to 70 years 3. For younger adults, the value is about 25 kcal/kg body weight/day, and for older adults, 22 kcal/kg body weight/day. BMR of obese or malnourished subjects must be estimated from actual, and not ideal body weight.
3.1. Harris-Benedict Equation
Basal Metabolic Rate (BMR) Caloric Needs: Harris-Benedict Equation
Basal Metabolic Rate (BMR) is the number of calories burned per day at rest. It is also considered the minimum amount of energy required to keep the body functioning. Many factors influence BMR including weight, height, age, and gender. BMR is considered the most important component of energy expenditure and accounts for roughly 70% of daily caloric needs.
There are a variety of different BMR equations. In this particular project, the Harris-Benedict equation is being implemented as that is one of the most widely used equations. It was formulated in 1919 and was one of the first equations used to calculate BMR 4.
Women’s Equation: BMR = 655 + (9.56 × weight in kg) + (1.85 × height in m) – (4.68 × age in years)
Men’s Equation: BMR = 66.5 + (13.75 × weight in kg) + (5.0 × height in m) – (6.76 × age in years)
4. Determining Total Daily Energy Expenditure (TDEE)
In order to understand what caloric needs someone may require daily, Total Daily Energy Expenditure (TDEE) should be understood. TDEE is the total amount of energy expended in a given day, and thus, the caloric needs for maintaining weight. TDEE must take into consideration not only the total amount of energy expended throughout the day but also the basal metabolic rate (BMR), which takes into account the factors of weight, height, age, and gender. Once the BMR is calculated, the TDEE can be calculated by taking this number and multiplying it by the activity levels of the subject 5.
TDEE has many daily uses, but calculating caloric needs based on weight is the starting point to understanding fat loss/gain. In understanding this, you will be able to set yourself up for whatever goal you may have and know how to adjust caloric intake based on the results you see 2. The amounts of calories that dictate winning vs losing a tug-of-war comes down to understanding TDEE and caloric needs, and by extension how that alters for individuals based on their weight.
4.1. Activity Levels
Once a person finds out their basal metabolic rate (BMR), they must determine their total daily energy expenditure (TDEE). An individual’s TDEE accounts for all calories expended during the day, including BMR caloric expenditure and additional calories burned through activity. TDEE can be calculated by simply multiplying BMR by a number that equates to that particular individual’s activity level. There are a few standard activity levels that one can use when figuring this value.
This factor is 1.2 for people who lead a sedentary lifestyle (do little or no exercise). This leads to a TDEE equal to BMR multiplied by 1.2. 1.375 is the activity factor for people who exercise lightly (light exercise/sports 1-3 days/week); TDEE equals BMR multiplied by 1.375. For people who are moderately active (moderate exercise/sports 3-5 days/week), the activity factor is 1.55; this leads to a TDEE of BMR multiplied by 1.55. 1.725 is the activity factor for people who exercise intensely (hard exercise/sports 6-7 days a week); TDEE equals BMR multiplied by 1.725.
Finally, for people with an extremely active lifestyle (very hard exercise, physical job, training twice a day, etc.), the activity factor is 1.9; this yields a TDEE equal to BMR multiplied by 1.9.
Once BMR is calculated, the number must be multiplied by the appropriate activity level, and the TDEE is found. It is appropriate to take into consideration the last two weeks of activity before calculating TDEE. If the person is entering a new routine, it is better to look at the weeks preceding that shift instead to ascertain an accurate depiction of what they have done previously. Generally, to gain weight, one should eat in excess of their TDEE. To lose weight, one has to eat less than their TDEE. For maintenance, TDEE should equal caloric intake.
Also read: How Many Calories Do You Burn During 21 Day Fix Cardio Exercises?
5. Specific Caloric Needs for Individuals Weighing 80 kg
Caloric needs vary based on several factors, including weight, height, age, gender, and activity level. The Basal Metabolic Rate (BMR) gives a baseline idea of how many calories are consumed at rest. Weight can be used in the BMR calculation to estimate caloric needs. The activity multiplier shows a range for activity levels to adjust caloric needs appropriately for individual lifestyles.
The BMR estimation using the Mifflin-St Jeor formula is the most accurate in estimating the BMR and caloric needs for the general population. For men, the formula is BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5. For women, it is BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161. The weight in this calculation specifies a height and age.
For example, suppose an 80 kg male is 180 cm tall and is 25 years old. His BMR will be 10 × 80 + 6.25 × 180 – 5 × 25 + 5 = 1857.5. A sedentary activity level means it is multiplied by 1.2, suggesting 2230.5 total caloric needs. Adjusting activity level, if moderately active, would multiply that number by 1.55 to suggest 2889.1 daily caloric needs.
The total daily energy expenditure (TDEE) is used to find caloric needs to maintain weight. It adds activity levels to BMR to find a daily caloric need. For an individual weighing 80 kg, TDEE is found by using the weight to calculate BMR through Mifflin-St Jeor, translating height and age into terms of weight, and adjusting BMR using activity multipliers for lifestyle fit. A sedentary lifestyle multiplied BMR by 1.2, adjusting total daily caloric needs to 2,125 kcal. A moderately active lifestyle multiplies BMR by 1.55 to suggest 2,393 kcal daily caloric needs. Very active lifestyles multiply BMR by 1.725 to suggest 3,149 kcal daily caloric needs.
References:
1. P Yuchingtat G. Previous Diet and Basal Metabolic Rate. 1992. [PDF]
2. Kreymann G, Adolph M, J. Mueller M. Energy expenditure and energy intake – Guidelines on Parenteral Nutrition, Chapter 3. 2009. ncbi.nlm.nih.gov
3. M. Abdel-Mageed S, I. Mohamed E. Total Body Capacitance for Estimating Human Basal Metabolic Rate in an Egyptian Population. 2016. ncbi.nlm.nih.gov
4. Claudine Luy S, Allan Dampil O. Comparison of the Harris-Benedict Equation, Bioelectrical Impedance Analysis, and Indirect Calorimetry for Measurement of Basal Metabolic Rate among Adult Obese Filipino Patients with Prediabetes or Type 2 Diabetes Mellitus. 2018. ncbi.nlm.nih.gov
5. Ogata H, Kobayashi F, Hibi M, Tanaka S et al. A novel approach to calculating the thermic effect of food in a metabolic chamber. 2016. ncbi.nlm.nih.gov