WHAT IS THE CAUSE OF OBESITY?
Obesity is a consequence of energy imbalance. The energy intake becomes excessive over energy consumption in a given period which leads to an increase in nutritional stores in the body. Multifactorial, complex influence of many factors cause the creation of a positive energy balance:
- genetic factors,
- biological factors (gender, age, pregnancy in women, hormonal activity),
- psychological factors and
- other factors and personal factors that interactively determine individual sensitivity to weight gain.
The impact of changes in external fortunes and social forces, economic situation, including behavioral changes (habits in the program, favorable physical activity) are a conciliatory reason for the appearance of the problem of global obesity.
Dietary factors and reduced levels of physical activity have been identified as “major” modifying factors that participate in the process of weight gain.
Energy balance
The fundamental principle of energy balance and regulation is:
Changes in energy stores are equal to energy intake minus energy consumption. Under normal circumstances, the energy balance oscillates continuously without the appearance of persistent changes in weight. Multiple physiological mechanisms equalize each individual the overall energy intake and consumption with which they maintain their stable weight over a long period of time.
Energy input
The first element of the energy balance is expressed in the form of an equation. It is total energy intake refers to overall energy consumed as food and beverages that can be metabolized into the organism. At the same time, the size of the input energy depends on the macronutrient composition of foods and beverages that provide energy.
Fats provide the most metabolically available energy per unit weight (9 kcal/g). Carbohydrates and proteins provide less energy (4 kcal/g). Fibrous fibers produce fatty acids that our body absorbs as energy (1.5 kcal/gr).
Energy consumption
Generally, three main components compose the total energy consumption, as the second element of energy balance:
a) Basal metabolic consumption or amount (BMR).
It is in fact the amount of energy our body needs to maintain the body’s vital functions. To estimate the total energy consumption, we should basically multiply the determined BMR by a cofactor (k). That includes energy consumption during increased muscle tone, physical activity, the thermal effect of feeding and energy needs relevant to reality.
b) “Thermic effect of food” (TEF)
The increased oxygen uptake referred to as “specific dynamic action after meals” or “thermic effect of food” (TEF) depends on the nutritional composition of the food consumed and the amount of energy ingested also.
c) Level of physical activity (Physical Activity Levels-PALs)
We do not consider obesity as a sharply defined syndrome. Individuals differ significantly in genetic subtypes as well as the level, type, and degree of metabolic disorders. Thus, the graded thermogenic response to food in obese individuals varies inversely with the degree of insulin resistance or impaired glucose tolerance.