Human Body Composition: Analysis, Techniques, and Evolutionary Diet

Posted on Dec 1, 2024 in Physical Education

Body Composition

  • It is the study of the parts of a whole, in this case, the human body (Rodriguez C. 1992).
  • Body analysis allows us to quantify the body’s components.
  • Body weight consists of many components or proportions that vary among individuals.
  • With the introduction of the microscope in the seventeenth century, researchers could penetrate tissues and cells. Analysis of tissues from biopsies has contributed significantly to our understanding of physiology and human metabolism.
  • Early studies on body composition were based on the chemical analysis of organs.
  • From this first model, the body’s compartmentalization was defined:
  • Fat mass (FM) and fat-free mass (FFM), represented by the general equation: MCT = MG + MLG

  • Total Body Mass (MCT)

  • Represents the sum of all body compartments. Considering that it measures body fat and fat-free mass (including all fluids), changes in any of these compartments are reflected in an individual’s body weight.
  • These concepts were developed by Behnke and colleagues in 1942, pioneers of determining total body density using hydrodensitometry or underwater weighing.

  • Densitometry (Hydrodensitometry or Underwater Weighing)

    The body volume is obtained based on Archimedes’ principle: the volume of an immersed object equals the volume it displaces. Measuring body volume requires measuring the individual’s weight in air and under complete immersion in a water tank. It demands high cooperation from the person.
  • Several models represent body composition: chemical or molecular (Ps, Ls, Ch, and min) and anatomical (tissues: fat, muscle, organs, bones).
  • Body composition measurements in clinical trials can establish: defining nutritional therapies, assessing risk, and preparing diagnoses. Thus, they are a constituent part of Nutritional Status Assessment.

  • Techniques to Measure

    Manual (plicometry), electrical conductivity, ultrasound, radiological.
Factors Affecting Body Composition
  • Age: Water content decreases with age, while protein and fat increase.
  • Exercise: Increases lean mass and decreases fat.
  • Pathologies.
  • Pregnancy.
  • Diet.
  • Distribution: Pear and apple.

Proper Fat in Sedentary People

AGE: 0-30, 31-40, 41-50, 51-60, 61-100, DECREASED, HIGH

WOMEN (%): 22-31, 20-26, 21-27, 22-28, 22-30, 32, ≤8

MEN (%): 12-18, 13-19, 14-20, 16-20, 17-21, 25, ≤5

Percentage of Overall Body Composition

  • Muscle Mass: 41.9 – 59.4%
  • Bone mass: 16.3 – 25.7%
  • Residual mass: 24.0 – 32.4%
    • Currently, a value commonly used in diagnosing malnutrition (excess or deficit) is the Body Mass Index (BMI), originating from statistics collected by the Belgian mathematician and astronomer Adolphe Quetelet (weight / height2).

    Rating:

    Lower Limit: 12g survival

    Wasting (Severe DN): <15

    Underweight: 15 – 18.9

    Normal: 19 – 24.9

    Overweight: 25 – 29.9

    Obesity: 30 – 39.9

    Severe Obesity: >40

    • Using an individual’s weight without considering body composition differences may lead to misclassifications.
    • Physical activity decisively influences body composition. Athletes tend to maintain a low, healthy fat percentage and increase lean mass (muscle), which adjusts body water content.


  • “In human history, diet has been the strongest evolutionary factor.”
  • Although initially based solely on fruit, the human diet expanded to include other plant foods like roots and nuts, promoting changes in human development, such as teeth and mastication mechanics.
  • Cultural strategies also emerged, such as using stones to crack nuts and producing sharp stones to cut food.
  • Upright posture facilitated adaptation to life under the sun, allowing hominids to cover greater distances when predators slept.
  • Our ancestors discovered scavenging, accessing fat and protein reserves in the marrow of dead animals’ long bones.
  • Consuming energy sources led to brain development.
  • In the Paleolithic period, consuming fish, small animals, and shellfish, along with plants and fruits, was crucial for evolutionary change, corresponding to the genetic structure we inherited. This dietary pattern is called the Paleolithic diet.
  • With the advent of agriculture and livestock, the human diet drastically changed.
  • Cereals contributed up to 90% of the diet, with very low animal protein intake.
  • Increased food production efficiency generated surpluses, leading to profound demographic changes, social classes, bureaucracies, and ultimately, cultural, food technology, and social development.
  • The imbalance in agrarian societies’ diets explains the emergence of diseases like protein-energy malnutrition, reduced member size, and the chronic diseases we face today.
  • The latest dietary change is recent, resulting from the industrial revolution.
  • Intensive agriculture and food technology have made available items not present during much of hominid evolution: fats, refined sugars, and vegetable oils.

  • Changes in Modern Food

    1. Increased energy intake and decreased energy expenditure.
    2. Increased saturated fat consumption and lower omega-3 fatty acid intake.
    3. Decreased fiber and complex carbohydrate consumption.
  • “In terms of genetics, modern humans live in a nutritional environment that differs from that for which our genetic constitution was selected.”
  • This is a short period (10,000 years) in which selective pressures haven’t produced new adaptive changes.
  • The contradiction between the modern diet and the genetic structure adapted to the Paleolithic diet is known as “evolutionary dietary discordance.”
  • Current epidemics of obesity, diabetes, hypertension, dyslipidemia, etc., result from evolutionary discordance.
  • In older humans, the genetic structure prioritizes defending energy reserves in a metabolic pattern suited for intense physical activity, which is no longer the case.
  • Given that genetic modification seems out of reach, modifying the current epidemiological picture requires returning to some aspects of the Paleolithic lifestyle: increased fruit and vegetable consumption, polyunsaturated fats, less fat, and more exercise.
Definitions
  • Food: Feeding
  • Nutrition: A set of biological and psychosocial processes subsequent to feeding, finely interwoven and regulated.
  • Ingestion, digestion, metabolism, and excretion of each cell. Environment.
  • Eating is an inescapable biological need for life preservation. However, for humans, it is much more: a pleasurable sensory stimulus, a means of aesthetic expression, communication, an effective instrument of social bonding, a central element of rituals, festive celebrations, and mourning ceremonies, an instrument to maintain and strengthen identity, and a way to express cultural peculiarities.
  • Achieving proper nutrition requires sufficient food variety at home, culinary skills, hygiene for preservation and preparation, judicious distribution among family members, suitable meal density and frequency, minimizing misinformation, and reducing losses and animal consumption.
  • Domestic food availability depends on acquisition or production if the family is active. It requires purchasing power and community availability, linked to regional, national, and even global food availability.
    NOTE: Meeting all these premises is challenging, and nutritional disorders of varying degrees are inevitable.