Obesity and Overweight
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Abstract
Obesity has become a significant public health issue worldwide over the last four decades.[1] It is caused by excess body fat accumulation, which is harmful to health. Obesity is defined by the World Health Organization (WHO) as body mass index (BMI) ≥30 kg/m2, while overweight is the BMI of ≥25 kg/m2.[2] The prevalence of overweight and obesity is increasing globally in both developing and developed countries in all age groups.[3] Since 1980, globally, its prevalence is almost doubled.[4] The WHO has reported that in 2016, more than 1.9 billion adults were overweight; among them, 650 million were obese.[5] In the United States, the prevalence exceeds 30% in most sex and age groups.[6] Besides, this trend of weight gain is present in children and adolescents and poses a significant threat to the population's present and future health status.[7] In Germany, overweight and obesity among children aged 3–17 years are 15.4% and 5.9%, respectively.[8] In developing countries, the prevalence of childhood obesity in 5–19 years old is reported as 41.8% in Mexico, 22.1% in Brazil, 22.0% in India and 19.3% in Argentina.[9] From 1975 to 2016, the prevalence of overweight or obese children and adolescents aged 5–19 years increased more than four-fold, from 4% to 18% globally.[10] There are several causes of overweight and obesity, including lifestyle factors such as diet and physical activity; genetic factors such as parental obesity, underlying disease conditions and medication use and demographic factors such as age, gender, place of habitat, education level and income.[1112] The energy imbalance between calories consumed and calories burned is considered a significant cause of obesity. The energy is consumed from food and drinks while energy is burned through physical activity, body temperature regulation, breathing, digestion, etc., If the energy intake is more by the body than the expenditure, overweight and obesity result as the excess amount of calories is stored as fat in the body.[3] The modern lifestyle differs from the earlier time when people used to be more active and struggled to obtain food. The growing urbanisation and changing dietary habits in modern lifestyles largely contribute to obesity of the people. Nowadays, people are taking foods with high-fat content, high sugar content and often large-sized food causing overeating; combined with this sedentary behaviour, television watching and less physical activity cause a global rise in obesity.[11112] Dietary changes also include reduced intakes of complex carbohydrates and dietary fibre and reduced fruit and vegetable intake. Studies showed that eating quickly is associated with overweight adolescents due to excessive energy intake.[11] The effect of urbanisation makes people take advantage of technologies, cars and other mechanical aids, which causes a decline in physical activity. Urbanisation also enables a more excellent food choice at a lower price, rich in calories due to energy density, contributing to weight gain.[13] Several socioeconomic factors such as knowledge, attitudes, economic and other constraints on nutrition and physical activity are related to child adiposity.[1] A study in Germany showed that children who grow up with low socioeconomic status are more likely to be overweight and obese than those with high socioeconomic status.[8] Economic factors are related to participation in physical activity and buying of food.[14] There is evidence that underlying genetic component influences the prevalence of obesity. Parental obesity is highly related to the obesity of children, accounting for the heritability of obesity to be between 40% and 70%.[15] In recent decades, the combined effects of environmental factors, genetic factors and individual lifestyle behaviour have been documented to cause excess weight gain.[16] In obesity, chronic, low-grade inflammation combined with dyslipidaemia causes vascular dysfunction, atherosclerosis and impaired fibrinolysis. These factors make the individual susceptible to cardiovascular disease, stroke and venous thromboembolism. Furthermore, chronic inflammation contributes to insulin resistance and type 2 diabetes.[17] Obesity is the main component related to obstructive sleep apnoea caused by fat deposition in the respiratory tract causing narrowing of the lumen of the respiratory tract. Thereby, reduces chest compliance due to decreased muscle activity, leading to hypoxia and apnoeic episodes.[18] Cancers are also significantly associated due to these underlying factors.[17] Obesity in children is related to metabolic diseases, non-alcoholic fatty liver disease and gastroesophageal reflux disease. It also affects growth and sexual development and may delay puberty in boys, advance puberty in some girls and cause psychological problems.[17] Obesity is a complex, multifactorial disease that leads to many comorbidities and mortalities. Overweight and obesity are significant contributing factors to developing several physical and mental disorders.[3] Obesity is considered a severe public health disease associated with non-communicable diseases. It is a risk factor for cardiovascular disease, type 2 diabetes, hypertension and cancers, causing many premature mortalities worldwide.[15] Obesity also has an excellent association with metabolic and renal disorders that pose a significant public health threat.[4] Stroke, kidney disease, breathing problems, sleep apnoea, osteoarthritis, malignancy, depression and anxiety are related to obesity and overweight. In addition to severe illness, there is a significant relationship between obesity and mortality. Obesity causes a decrease in life expectancy of 5–10 years[17] and almost doubles in people who smoke.[19] Quality of life is affected in obese people, and their economic and psychological burdens are exacerbated due to underlying physical and psychosocial problems.[6] It also imposes a significant load on the economy of the country. Healthcare cost related to obesity is also an important issue. It is up to 10.4 billion Euros in Europe, 2.74 billion US dollars in China and 6.0 billion US dollars in Canada.[16] In the United States, obesity accounts for more than 20% of all annual healthcare expenditures.[6] It is evidenced that overweight and obese children are more susceptible to cardiovascular disease, hypertension, hyperinsulinaemia, dyslipidaemia and chronic kidney damage.[2021] These are all associated with underlying hormonal changes and vascular dysfunction leading to cardiovascular disease in adulthood.[21] Furthermore, overweight and obesity in children and adolescents are related to psychological problems such as depression, anxiety, low self-esteem and lack of cognitive stimulation. They are also victims of bullying with a significant reduction in quality of life.[22] Prevention of obesity by targeting the contributing factors, lifestyle and active involvement of the supporting health services is of great importance and has been advocated in recent years. The prevention program must be adopted at the individual, family, community and national levels. Good eating habits and physical activity can be emphasised by educating people at schools and workplaces and the community. The home environment is an essential setting in preventing overweight and obesity, the need for widespread dissemination of knowledge to the parents and family in this regard. Restricting time for television viewing and not taking extra food during watching is an important strategy to bring healthy foods, practice regular meal times and participate in physical activities. Parents can act as role models for healthy eating.[16] At school level, knowledge dissemination can be done through physical education teaching and inspiring them to walk or bike to school.[6] It has been advocated that national government should embrace new strategies by increasing taxes on unhealthy food such as sugar sweetened beverages (SSBs) and in contrast increase subsidizes towards healthy foods.[6] Trained healthcare professionals must monitor the patients regularly and motivate them to control their obesity.[6] The American Heart Association published a comprehensive population-based approach to healthful eating, physical activity and energy balance for obesity prevention.[23] In 2009, the Centers for Disease Control and Prevention[24] issued 24 strategies divided into six categories for obesity prevention. Individual behavioural change is the core of all strategies. The strategies are as follows: (1) strategies to promote the availability of affordable healthy food and beverages, (2) strategies to support healthy food and beverage choices, (3) a strategy to encourage breastfeeding, (4) strategies to encourage physical activity or limit sedentary activity among children and youth, (5) strategies to create safe communities that support physical activity and (6) a strategy to encourage communities to organise for change.[24] Obesity is a complex condition that leads to several diseases with significant mortality and morbidity. It is necessary to educate the people with all the required information and tools to motivate them and employ prevention strategies at governmental, organizational, community, family, and individual levels. Consent for publication The author reviewed and approved the final version and has agreed to be accountable for all aspects of the work, including any accuracy or integrity issues.