Schofield equation

Last updated

The Schofield Equation is a method of estimating the basal metabolic rate (BMR) of adult men and women published in 1985. [1]

Contents

This is the equation used by the WHO in their technical report series. [2] The equation that is recommended to estimate BMR by the US Academy of Nutrition and Dietetics is the Mifflin-St. Jeor equation. [3]

The equations for estimating BMR in kJ/day (kilojoules per day) from body mass (kg) are: [4]

Men:

AgeEquation (kJ/day)SEE
< 3249 × W - 127292
3–1095 × W + 2110280
10–1874 × W + 2754441
18–3063 × W + 2896641
30–6048 × W + 3653700
> 6049 × W + 2459686

Women:

AgeEquation (kJ/day)SEE
< 3244 × W - 130246
3–1085 × W + 2033292
10–1856 × W + 2898466
18–3062 × W + 2036497
30–6034 × W + 3538465
> 6038 × W + 2755451

The equations for estimating BMR in kcal/day (kilocalories per day) from body mass (kg) are:

Men:

AgeEquation (kcal/day)SEE
< 359.512 × W - 30.470
3–1022.706 × W + 504.367
10–1817.686 × W + 658.2105
18–3015.057 × W + 692.2153
30–6011.472 × W + 873.1167
> 6011.711 × W + 587.7164

Women:

AgeEquation (kcal/day)SEE
< 358.317 × W - 31.159
3–1020.315 × W + 485.970
10–1813.384 × W + 692.6111
18–3014.818 × W + 486.6119
30–608.126 × W + 845.6111
> 609.082 × W + 658.5108

Key:

W = Body weight in kilograms

SEE = Standard error of estimation

The raw figure obtained by the equation should be adjusted up or downwards, within the confidence limit suggested by the quoted estimation errors, and according to the following principles:

Subjects leaner and more muscular than usual require more energy than the average. Obese subjects require less. Patients at the young end of the age range for a given equation require more energy. Patients at the high end of the age range for a given equation require less energy.

Effects of age and body mass may cancel out: an obese 30-year-old or an athletic 60-year-old may need no adjustment from the raw figure.

Physical activity levels

To find total body energy expenditure (actual energy needed per day), the base metabolism must then be multiplied by an physical activity level factor. These are as follows:

ActivityMaleFemaleDescription
Sedentary 1.31.3Very physically inactive, inactive in both work and leisure.
Lightly active1.61.5Daily routine includes some walking, or intense exercise once or twice per week. Most students are in this category.
Moderate activity1.71.6Intense exercise lasting 20–45 minutes at least three time per week, or a job with a lot of walking, or a moderate intensity job.
Very active2.11.9Intense exercise lasting at least an hour per day, or a heavy physical job, such as a mail carrier or an athlete in training.
Extremely active2.42.2Extremely active means an athlete on an unstoppable training schedule or a very demanding job, such as working in the armed forces or shoveling coal.

The FAO/WHO uses different PALs in their recommendations when recommending how to calculate TEE. See Table 5.3 of their working document. Energy Requirements of Adults, Report of a Joint FAO/WHO/UNU Expert Consultation [5] .

These equations were published in 1989 in the dietary guidelines and formed the RDA's for a number of years. The activity factor used by the USDA was 1.6. In the UK, a lower activity factor of 1.4 is used. The equation has now been replaced by the Institute of Medicine Equation in September 2002 in the US, however is still currently used by the FAO/WHO/UNU.

See also

Related Research Articles

An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms, the nine amino acids humans cannot synthesize are valine, isoleucine, leucine, methionine, phenylalanine, tryptophan, threonine, histidine, and lysine.

Human body weight is a person's mass or weight.

Basal metabolic rate (BMR) is the rate of energy expenditure per unit time by endothermic animals at rest. It is reported in energy units per unit time ranging from watt (joule/second) to ml O2/min or joule per hour per kg body mass J/(h·kg). Proper measurement requires a strict set of criteria to be met. These criteria include being in a physically and psychologically undisturbed state and being in a thermally neutral environment while in the post-absorptive state (i.e., not actively digesting food). In bradymetabolic animals, such as fish and reptiles, the equivalent term standard metabolic rate (SMR) applies. It follows the same criteria as BMR, but requires the documentation of the temperature at which the metabolic rate was measured. This makes BMR a variant of standard metabolic rate measurement that excludes the temperature data, a practice that has led to problems in defining "standard" rates of metabolism for many mammals.

Resting metabolic rate (RMR) is whole-body mammal metabolism during a time period of strict and steady resting conditions that are defined by a combination of assumptions of physiological homeostasis and biological equilibrium. RMR differs from basal metabolic rate (BMR) because BMR measurements must meet total physiological equilibrium whereas RMR conditions of measurement can be altered and defined by the contextual limitations. Therefore, BMR is measured in the elusive "perfect" steady state, whereas RMR measurement is more accessible and thus, represents most, if not all measurements or estimates of daily energy expenditure.

The body fat percentage (BFP) of a human or other living being is the total mass of fat divided by total body mass, multiplied by 100; body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive functions. The percentage of essential body fat for women is greater than that for men, due to the demands of childbearing and other hormonal functions. Storage body fat consists of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen. A number of methods are available for determining body fat percentage, such as measurement with calipers or through the use of bioelectrical impedance analysis.

Energy consumption is the amount of energy used.

Biological value (BV) is a measure of the proportion of absorbed protein from a food which becomes incorporated into the proteins of the organism's body. It captures how readily the digested protein can be used in protein synthesis in the cells of the organism. Proteins are the major source of nitrogen in food. BV assumes protein is the only source of nitrogen and measures the amount of nitrogen ingested in relation to the amount which is subsequently excreted. The remainder must have been incorporated into the proteins of the organisms body. A ratio of nitrogen incorporated into the body over nitrogen absorbed gives a measure of protein "usability" – the BV.

<span class="mw-page-title-main">Protein (nutrient)</span> Nutrient for the human body

Proteins are essential nutrients for the human body. They are one of the building blocks of body tissue and can also serve as a fuel source. As a fuel, proteins provide as much energy density as carbohydrates: 4 kcal per gram; in contrast, lipids provide 9 kcal per gram. The most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition.

<span class="mw-page-title-main">Physical activity level</span>

The physical activity level (PAL) is a way to express a person's daily physical activity as a number, and is used to estimate a person's total energy expenditure. In combination with the basal metabolic rate, it can be used to compute the amount of food energy a person needs to consume in order to maintain a particular lifestyle.

The Institute of Medicine Equation was published in September 2002. It is the equation which is behind the 2005 Dietary Guidelines for Americans and the new food pyramid, MyPyramid.

<span class="mw-page-title-main">Overweight</span> Above a weight considered healthy

Being overweight or fat is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary.

Lean body mass (LBM), sometimes conflated with fat-free mass, is a component of body composition. Fat-free mass (FFM) is calculated by subtracting body fat weight from total body weight: total body weight is lean plus fat. In equations:

The Harris–Benedict equation is a method used to estimate an individual's basal metabolic rate (BMR).

<span class="mw-page-title-main">Diet and obesity</span> Effect of diet on obesity


Diet plays an important role in the genesis of obesity. Personal choices, food advertising, social customs and cultural influences, as well as food availability and pricing all play a role in determining what and how much an individual eats.

In biology, energy homeostasis, or the homeostatic control of energy balance, is a biological process that involves the coordinated homeostatic regulation of food intake and energy expenditure. The human brain, particularly the hypothalamus, plays a central role in regulating energy homeostasis and generating the sense of hunger by integrating a number of biochemical signals that transmit information about energy balance. Fifty percent of the energy from glucose metabolism is immediately converted to heat.

<span class="mw-page-title-main">Weight management</span> Techniques for maintaining body weight

Weight management refers to behaviors, techniques, and physiological processes that contribute to a person's ability to attain and maintain a healthy weight. Most weight management techniques encompass long-term lifestyle strategies that promote healthy eating and daily physical activity. Moreover, weight management involves developing meaningful ways to track weight over time and to identify ideal body weights for different individuals.

A calorie deficit is any shortage in the number of calories consumed relative to the number of calories needed for maintenance of current body weight.

Paul Deurenberg is a Dutch retired academic, nutritional biochemist and consultant. He was a former associate professor in the Department of Human Nutrition at Wageningen University (WU), and is most known for his research expertise in the areas of energy metabolism, food consumption, and body composition studies.

<span class="mw-page-title-main">Horse body mass</span> Horse body weight and weight measurement

The horse body mass is highly variable, depending on breed, model, physiological state, condition, owner's purpose and usage of the animal. Always 65 % to 75 % water, it is divided on average between 50 % muscle, 11 % bone and 10 % fat. Depending on whether it's a pony or a draft horse, it can range from less than 200 kg to over a ton, with an average of 500 kg for saddle horses. It also differs with the season, as horses are almost always fatter in summer than in winter. Various tools are used to estimate their weight and body condition, and veterinary scales have been created to determine whether a horse has an ideal body mass according to precise criteria. Thinness is associated with mistreatment, but owner-independent factors such as age and illness can cause dramatic weight loss in horses. In Western countries, equine obesity is one of the major veterinary health problems of the 21st century. It is directly linked to numerous pathologies, such as laminitis, osteoarthritis, insulin resistance and colic. It also favors the development of equine Cushing's disease, and causes a drop in stallion fertility.

Energy expenditure, often estimated as the total daily energy expenditure (TDEE), is the amount of energy burned by the human body.

References

  1. Schofield WN (1985). "Predicting basal metabolic rate, new standards and review of previous work". Human Nutrition: Clinical Nutrition. 39 Suppl 1: 5–41. PMID   4044297.
  2. World Health Organisation, Fao, and Unu. Energy and protein requirements. Geneva: WHO, Technical Report Series 724, 1985.
  3. J Am Diet Assoc. 2009;109:330-346.
  4. Energy Requirements of Adults, Report of a Joint FAO/WHO/UNU Expert Consultation, (See table 5.2).
  5. "Human energy requirements". www.fao.org. Retrieved 2023-12-25.