Is it genuinely the case that others can diminish their body mass index and I am unable to do so?

In human development, there are so-called critical periods during which the body is programmed, which can impact later health. This process commences in the mother's womb, hence it is not insignificant how she nourishes herself. In epidemiological studies, it has been observed that excessive adipose tissue in mothers predisposes offspring to higher birth weight, which in turn is a factor that increases the risk of obesity. Fascinatingly, a parent's underweight can lead to the same outcome. This is explained by the fact that the child's body, accustomed to nutritional deficiency, requires more food in the presence of sustenance to prepare for a potential deficiency in the future. The presence of type 2 diabetes and gestational diabetes in mothers is also of great importance, as they contribute to higher birth weight and an increased risk of obesity in children, as well as reduced glucose tolerance (E. L. Sullivan, K. L. Grove 2010).

Although environmental and individual factors have the greatest impact on the development of overweight, it turns out that genes also play a significant role. Research has discovered over 300 unique genes and gene markers that are associated with obesity and that, when activated by the environment, can lead to weight gain. It is also believed that genetics influences the amount of fat tissue, its distribution, the percentage of lean body mass, as well as dietary habits and the inclination towards physical activity (J. -P. Chaput et al., 2014).

A rare type of obesity is hypothalamic obesity, which is the result of damage to the hypothalamus, responsible for regulating physiological processes, leading to disturbances in hunger and satiety signals, and ultimately, to excessive food intake and uncontrolled weight gain. Another disease that affects body weight is Cushing's syndrome, caused by excessive exposure of the body to glucocorticoids, leading to increased production and storage of fat tissue, mainly in the face, neck, and abdomen. A frequently occurring disease is hypothyroidism, which is associated with weight gain. Excess androgens in the course of polycystic ovarian syndrome (PCOS) lead to increased fat accumulation in the abdominal area. Due to limited mobility, disabled people have a much lower energy expenditure than the rest of the population, leading to a sedentary lifestyle and an increased risk of developing metabolic diseases. Among the medications that affect body weight are antidepressants, antipsychotics, antidiabetics, antiepileptics, antihistamines, blood pressure-lowering drugs, hormonal contraceptives, and steroids. In animal studies, it has been found that the composition of the gut microbiota can also influence body weight.

Nowadays, access to food is almost unlimited, especially in developed countries. There are also more and more processed and energy-rich foods on the market, making it easy to exceed calorie intake. Snacks, fast-food or sweets are easily available and consuming these products is obviously easier than preparing a healthy meal. Sweetened drinks and juices are also popular, providing a lot of energy. However, they are not perceived as a source of calories and the knowledge about their caloric contents is often insufficient. It is also important that eating has become a social event and not just an energy source, but also a way to spend time with others. Another problem is the advertising of processed foods in the media, which particularly affects children. A lifestyle characterized by stress and haste, focusing on career and leaving little time for self-care does not favor maintaining a healthy body weight. Studies have shown that eating during work or in a different hectic lifestyle leads to overconsumption (A. M. Andrade et al. 2012). Another important issue is that most people have a sedentary lifestyle, which leads to less physical activity and thus a lower energy requirement. The main form of leisure activities, such as surfing the internet and watching television, often leads to snacking and overconsumption of snacks, which leads to overconsumption of calories (K. Heller 2016). It has also been proven that a lower level of education and lower income are predisposing factors for the development of overweight. This is probably due to limited access to high-quality food and a lack of nutritional knowledge (T. Kim, O. von dem Knesebeck 2018). Research shows that adequate sleep is important for maintaining a healthy body weight. It has been shown that sleep deprivation leads to an increase in leptin and ghrelin levels (hormones that affect hunger and satiety), increased food intake, and more frequent snacking (S. M. Greer, A. N. Goldstein, M. P. Walker 2013).

The most common problem that leads to excessive food intake is the inability to manage emotions and reduce stress through eating, which is mostly accompanied by depression but also stressful situations or boredom. Unfortunately, at such times, the most commonly chosen products are sweets and foods that cause pleasant associations (e.g. happy childhood). People with an emotional outlook tend to have trouble sensing the signs of hunger and cravings and, consequently, they also get overwhelmed.

Although excess energy supply compared to demand is the primary cause of excess weight, the issue is much more complex than it appears. The susceptibility to weight gain is shaped during fetal life and can be modified throughout life due to a multitude of factors – both environmental and psychological, as well as genetic. Hence, it seems extremely important to commence education in proper nutrition from the earliest years.