30 November 2023
Understanding the obesity epidemic
Published online 22 October 2023
Deeper investigation is needed into the molecular mechanisms that control how we eat food and burn calories.
The underlying causes of obesity are much more complicated than over-eating or leading a sedentary lifestyle. A recent systematic review has revealed that despite a great deal of scientific discovery, there are still many questions about the molecular mechanisms leading to obesity
A study published in Science, led by Thorkild Sørensen, professor of Public Health at the University of Copenhagen, found there is a widespread belief that obesity results from either inherited genes or environment factors. “In reality, it is a combination of both. While genes can make us more or less vulnerable to obesity, environmental factors, such as our diet and activity level, play a crucial role in determining who develops the disease,” Sørensen told Nature Middle East.
“This incomplete knowledge makes us reject any bias about obesity being an intrinsic cause, that is, resulting from the failure of voluntary control over food intake and physical activity. We hope to combat such stigma and discrimination, which severely affects the quality of life of people with obesity,” he added.
Genetic and environmental factors
Based on 2023 estimates issued by the World Obesity Federation, more than four billion people (51% of the world’s population) will be obese by 2035, and the total cost of treating obesity-related diseases will reach $4.32 trillion annually. This is equivalent to the cost of the COVID-19 pandemic in terms of health care expenditures worldwide in 2020.
Childhood obesity is rising particularly fast. Rates are expected to double among boys by 2035 to 208 million, and to increase by 125% among girls to 175 million. In all, over 1.5 billion adults and nearly 400 million children will be obese within 12 years unless significant action is taken.
The Arab world
“The alarming global increase in obesity rates over the past few decades has been significantly reflected in the Arab world. The region has witnessed a unique interaction between the genetic and environmental factors that contribute to the spread of the obesity epidemic,” says Ahmed Mostafa, professor of Bioinformatics and Genomics at the American University in Cairo.
Kuwait has the highest obesity levels among adults in the Middle East and the Arab world with a prevalence of 34.28% among males and 47.08% among females, followed by Qatar (33.46% of males and 44.60% of females), and Saudi Arabia (31.73% of males and 43.74% of females). Among women in Jordan, 44.6% are obese.
“Recognizing the shift in dietary habits is fundamental to understanding the course of obesity in the Arab world. Economic growth and globalization have introduced Western dietary influences, replacing traditional diets rich in whole grains, vegetables, and lean proteins with refined sugars, unhealthy fats, and processed foods. These energy-rich, often aggressively marketed foods, are finding favor with populations keen to embrace modern dietary trends,” adds Mostafa in a statement to Nature Middle East.
Physical activity, an essential balance for dietary excesses, is lacking in the region, according to Mostafa. Cultural norms, especially those related to women, restrict outdoor activities. In addition, the hot climate makes sports and activity challenging.
“Environmental factors play an important role, but we cannot rule out a genetic predisposition that may make some people more susceptible to obesity. While global research has identified various genetic markers associated with obesity, there is an urgent need for more local studies in the Arab world. Unraveling these genetic threads would provide insights into why some segments of the population are more vulnerable to obesity than others,” said Mostafa.
Lifestyle and morbid obesity
Mostafa Al-Houti, a clinical nutrition and obesity treatment consultant in Egypt, said: “We should not ignore the causes of morbid obesity, resulting from thyroid diseases, or taking some medications such as cortisone medications used to treat allergies, hormone medications, psychiatric medications, and antidepressants, all of which cause side effects, notably including increased appetite, fluid retention, and subsequently weight gain. Identifying the underlying cause of obesity, whether resulting from lifestyle, medications, or any other reason, makes a significant contribution to treatment.”
Sørensen believes that the main goal of his recent study is to inspire researchers to further investigate the causes of obesity, and to understand the molecular mechanisms that control how we eat and burn calories.
“In our future attempts, we need to be open to understanding the causes of obesity, and ready to consider ideas that seem strange. A comprehensive theory about the development of obesity needs to integrate changes in the social environment, brain interaction with other organs and particularly with adipose tissue, and in many other components of the body’s metabolism as well.”