scientific analysis of disadvantages related to human Physiology of human body
Answers
Some features of human physiology contribute to the ease of gaining fat, such as human opportunistic predisposition to overeat palatable foods even when not hungry and the inability to directly detect energy eaten or expended through exercise. Other features contributing to obesity are the large capacity to store fat compared to non-human primates, and the vigorous metabolic, hormonal, and behavioral obstacles that restrain the loss of accumulated body fat. In addition, social pressures contributing to the ease of overeating include governmental food-availability policies, questionable institutional recommendations for nutrient selection, and advertising by food and restaurant industries that also provide convenient, maximally palatable, and often unhealthy food. The prevention and the reversal of obesity require awareness of the physiological limitations leading to human overeating and a presence of strong defenses against weight loss. As we cannot directly track calories eaten or expended, using sensations of fullness is our partial and limited guide against excessive food consumption. Several examples are provided here on how to limit or counteract a predisposition to seek out nutrients that, in excess, are detrimental, and to select nutrients that, sometimes contrary to public advice, are actually beneficial. Since our feeding mechanism is opportunistic rather than homeostatically regulated, the proposed solution in this review to prevention and reversal of obesity is to approach meals and nutrient intake with an understanding of the ease of overeating, the powerful mechanism resisting weight loss, and limited effectiveness of exercise-associated energy expenditure to counteract it.
The central thesis is presented in a series of five arguments:
(1) obesity has serious health and economic consequences and is predominantly driven by overconsumption of food rather than by inadequate contribution of energy expenditure through physical activity;
(2) overeating is primarily based on human predisposition for overconsumption of palatable foods, aided by governmental food-supply policies, less-than-ideal institutional recommendations for macronutrient intake, and commercial pressures for the sale of palatable food;
(3) the key problem facilitating overeating is human physiological inability to directly detect energy eaten or expended through physical activity;
(4) human evolution endowed humans, as opposed to non-human primates, with an impressive capacity for fat storage, and human physiology provides strong metabolic, endocrine, and psychophysical defenses against losses of body mass and stored energy regardless of the starting level of fatness; and
(5) an understanding of human physiological limitations permissive to overeating, and of difficulties against reducing body fat levels, exacerbated by societal pressures that facilitate overeating, represent a solution toward prudent selection of quantity and quality of nutrients to prevent obesity or mitigate some of its adverse effects.
2. Sustained Rise of Obesity Is Associated with Pathology and Economic Burdens
The economic and health burdens of obesity are largely a consequence of associated morbidities such as hypertension, atherosclerosis, hypercoagulability of blood, endothelial dysfunction, coronary vascular issues], kidney dysfunction, heart disease, stroke, and type 2 diabetes (T2D). The close association between obesity, peripheral tissue resistance to insulin action, and T2D is reflected in the frequently used descriptive term “diabesity”. Obesity-associated morbidities increase the risk of death by two- to threefold.
While, from a thermodynamic point of view, the energy loss of physical activity should contribute to body energy balance as much as actual energy consumed, the failure of exercise as electively practiced in developed society to produce substantial body fat loss [15,16] indicates that energy overconsumption [17] is the primary driver of the sustained rise in obesity