Determination of ideal body weight
To objectively assess nutritional status, a specialist needs to compare the patient's actual weight with their ideal (target) body weight. Various calculation methods are used for this purpose in hygienic and clinical practice.
The simplest and most orientational method uses Paul Broca's formula. It is based exclusively on a single anthropometric parameter: human height. The algorithm is extremely simple:
- Formula: Height (measured in centimeters) − 100 = Ideal body weight (in kilograms).
- Practice example: If the examinee's height is 170 cm, their ideal weight according to Broca will be 70 kg (since 170 − 100 = 70).
Despite its convenience, Broca's formula provides only an approximate result. A more accurate tool is A.A. Pokrovsky's table. This method simultaneously takes into account a whole complex of individual parameters: sex, exact age, height, and the person's constitutional type (body build).
Determination of constitutional type
In order to correctly use detailed tables (such as Pokrovsky's method), the physician must first establish the examinee's constitutional type. To this end, a special proportionality index is calculated, which demonstrates the ratio between chest circumference and height.
- Calculation formula: (Chest circumference (in cm) × 100) / Height (in cm).
The resulting numerical value allows the patient to be classified into one of three somatotypes. The interpretation of the index is as follows:
- Less than 50 — indicates asthenia (asthenic type). In such patients, the normal body weight will be the lowest for an equal height.
- From 50 to 55 — regarded as the physiological norm, which corresponds to the normosthenic type.
- More than 55 — indicates hypersthenia (hypersthenic type). People with this body build have a more massive frame, so their weight standards are higher.
Effect of food intake on energy expenditure
When assessing nutritional status and planning a diet, it is important to consider that after food intake, an increase in energy expenditure is always observed in the body.
The main cause of this phenomenon lies in the sharp activation of the activity of all digestive organs, as well as the work of the corresponding skeletal muscles (muscles involved in chewing, swallowing, and food propulsion). In addition, the final degree of increase in energy metabolism is significantly influenced by the composition of the food consumed by the person.
Pokrovsky's table: standards for ages 25–30
Below are the summary values of ideal body weight according to A.A. Pokrovsky for men and women in the 25–30 age group, depending on their height and identified constitutional type.
| Height, cm | Male (asthenic) | Male (normosthenic) | Male (hypersthenic) | Female (asthenic) | Female (normosthenic) | Female (hypersthenic) |
|---|---|---|---|---|---|---|
| 152,5 | - | - | - | 47,8 | 54,0 | 59,0 |
| 155,0 | 49,3 | 56,0 | 62,2 | 49,2 | 55,2 | 61,6 |
| 157,5 | 51,7 | 58,0 | 64,0 | 50,8 | 57,0 | 63,1 |
| 160,0 | 53,5 | 60,0 | 66,0 | 52,1 | 58,5 | 64,8 |
| 162,5 | 55,3 | 61,7 | 68,0 | 53,8 | 60,1 | 66,3 |
| 165,0 | 57,1 | 63,5 | 69,5 | 55,3 | 61,8 | 67,8 |
| 167,5 | 59,3 | 65,8 | 71,8 | 56,6 | 63,0 | 69,0 |
| 170,0 | 60,5 | 67,8 | 73,8 | 57,8 | 64,0 | 70,0 |
| 172,5 | 63,3 | 69,4 | 76,8 | 59,0 | 65,2 | 71,2 |
| 175,0 | 65,3 | 71,7 | 77,8 | 60,3 | 66,5 | 72,5 |
| 177,5 | 67,3 | 73,8 | 79,8 | 61,5 | 67,7 | 73,7 |
| 180,0 | 68,9 | 75,2 | 81,2 | 62,7 | 68,9 | 74,9 |
| 182,5 | 70,9 | 77,2 | 83,6 | - | - | - |
| 185,0 | 72,8 | 79,2 | 85,2 | - | - | - |
Briefly: answers to topical questions
What dietary characteristics determine the final degree of increase in energy metabolism after a meal?
The final degree of increase in energy metabolism after a meal directly depends on the qualitative composition of the food consumed, as well as its specific components. The greatest increase in metabolism is observed upon the intake of protein food, while carbohydrates and fats cause a significantly lesser effect. With the consumption of regular mixed food of balanced composition, the level of total metabolism increases by 10–12 percent relative to the basal metabolic rate.
What methods for assessing nutritional status are used in hygienic practice in addition to anthropometric ones?
In addition to anthropometric methods, clinical methods are used, including taking an anamnesis and objective examination, as well as laboratory-biochemical methods. Laboratory methods aim to assess the visceral protein pool, including the determination of albumin and short-lived proteins, in particular transferrin; short-lived proteins are earlier and more sensitive markers of nutritional deficiency.
What is the physiological phenomenon of increased energy expenditure after a meal called, and what are its exact values for proteins, fats, and carbohydrates?
The physiological phenomenon of increased energy expenditure of the body after a meal is called the specific dynamic action of food. The level of increase in energy expenditure directly depends on the nutrient composition of the diet and varies significantly for different nutrients. Upon protein intake, energy expenditure increases by 30–40 percent with an effect duration of 7–8 hours. Upon carbohydrate intake, energy expenditure increases by 4–6 percent within 2–3 hours, whereas fats cause only an insignificant increase in energy expenditure.
What anthropometric measurements, besides height, weight, and chest circumference, are used for a comprehensive assessment of nutritional status?
In addition to measuring body weight, body length (height), and chest circumference, arm muscle circumference is measured to assess somatic muscle protein, and skinfold thickness is measured using skinfold calipers to objectify the loss of subcutaneous adipose tissue.
Remembering the limits of the proportionality index is simple: "From fifty to two fives" (50–55) is the absolute norm (normosthenic). Anything less than 50 is asthenia, and more than 55 is hypersthenia.
Class and exam questions
What is the main drawback of Paul Broca's formula?
Broca's formula is only an orientational method. Unlike Pokrovsky's tables, it does not take into account the patient's sex, age, and individual constitutional type.
How to quickly understand which body build type a patient belongs to?
You need to measure their height and chest circumference. Then the chest circumference is multiplied by 100 and divided by the height. A result up to 50 will indicate an asthenic, 50–55 a normosthenic, and over 55 a hypersthenic.
Why does digestion require additional energy expenditure?
After food intake, the work of digestive glands, smooth muscles of the gastrointestinal tract, and skeletal muscles (e.g., masticatory muscles) is activated, which naturally increases the body's total energy expenditure.
What else to study on this topic
- The effect of the various component composition of food (proteins, fats, carbohydrates) on the degree of increase in energy expenditure.
- A.A. Pokrovsky's tables for other age groups (under 25 and over 30 years old).
- Anatomical and physiological features of patients with asthenic and hypersthenic constitutional types.
- Rules for performing anthropometry: how to accurately measure height and chest circumference to calculate the proportionality index.
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