Age, income, and lack of physical activity are the factors most associated with obesity in Brazil, according to FGV study

Six out of ten Brazilians are overweight in Brazil, and about 600 million people worldwide are considered obese, according to IBGE and WHO. Given this global public health problem, Fundação Getulio Vargas conducted an unprecedented study on obesity, using a multidimensional approach and integrating different factors that can lead to the occurrence of the disease. The research identified through statistical analyses that age, socioeconomic conditions, and lack of physical activity are the main factors associated with the prevalence of obesity in Brazil.

The project used data from the National Health Survey (PNS) and the Family Budget Survey (POF), both from IBGE, to understand the plausible causes of obesity through the main factors related to this disease in the country. Through an unprecedented approach, the project hopes to support the creation of public health policies, deepening knowledge on the topic and mapping the most effective measures to combat overweight worldwide.

Researcher Marcio Holland from the São Paulo School of Economics (FGV EESP), who coordinated the study, states that many people believe that obesity is mainly associated with the consumption of certain foods. However, the new study indicates that this factor is of little relevance when analyzed more broadly.

"When comparing individuals with normal weight and overweight, there were no statistically significant differences in caloric consumption, with the average difference being 5 Kcal. However, lifestyle and work mode, as well as the fact that an individual resides in urban areas, increase the probability of overweight," introduced the professor.

Obesity in low-income populations

Obesity is a disease caused by excess weight when an individual reaches a Body Mass Index (BMI) equal to or greater than 30 kilograms per square meter. In comparison, a person with normal weight usually has a BMI of 18 to 24.9 kilograms per square meter. Any number above this value can already be considered overweight, reported the researcher in the final study report.

PNS indicates that the current obesity rate in Brazil is 20.1%. However, FGV EESP researchers also projected the evolution of obesity in the country and found that if the disease continues with the same current growth rate, by 2030 it will reach 24.5% of the population. However, within this growth rate, some segments of society are more vulnerable.

Although obesity has increased in rich and poor countries, the study found that there is an imbalance between consumption and caloric expenditure in low-income populations. According to the research, some reasons pointing to greater vulnerability in this segment of society are related to access to cheaper and nutrient-poor foods with high caloric density. In addition, low education also limits access to nutritional information, impacting the eating habits of this population.

To understand the level of impact of each of these factors, whether direct or indirect, it is necessary to have a multidimensional perspective. "Given the complexity of its causes, the extent of its damages, and the status of a global epidemic, obesity control does not present a simple, direct, and obvious response," stated the study authors in the final project report, which will have its results disclosed during the webinar on Obesity in Brazil, which takes place on April 25th at 11 am on FGV's YouTube channel.

Childhood obesity and population aging

The study warns that childhood obesity is closely associated with the prevalence of this disease throughout a person's life, but this relationship is much more rooted than most individuals imagine, starting from breastfeeding. According to the research, there are indications that the hormones present in breast milk contribute to the baby's satiety, and this can be a strategy to reduce the risks of chronic diseases such as obesity.

In this scenario, early interruption of breastfeeding and lifestyle associated with means of transportation, combined with a high bias of sedentary behavior, are some of the multidimensional causes that contribute to childhood obesity.

This risk, according to researcher Marcio, tends to increase as the individual gets older, as children and adolescents have much lower obesity rates, reaching only about 6% of this part of the population. However, once obesity is established in youth, it becomes very difficult to reverse this condition into adulthood.

"The older you get, the higher the probability of becoming obese. Our country has a very accelerated population aging. On average, our population ages three times faster than populations of other countries that already have an older society. In recent decades, there has been a significant reduction in the young population in our country, and what took France 150 years to age, for example, Brazil did in 50 years," pointed out the researcher.

Obesity affects men and women differently

He adds that there is a female gender bias in the prevalence of obesity, despite the prevalence of overweight being higher among men. "This is a very interesting fact since women's obesity is not usually as severe as men's overweight. This is because weight gain in men is linked to the abdominal region and the possibility of cardiovascular diseases, in addition to affecting men more intensely in terms of mass locality," he informed.

Still, PNS data pointed to a prevalence of 22% obesity in women and 18% in men, while the overweight rate in men is 39% and 34% in women. The professor highlights that there are several reasons associated with women that are different from men when it comes to obesity.

He believes that the WHO classification for normal weight and overweight could be altered to categorize men and women equitably, defining degrees of obesity according to their respective factors. "Thus, it would be possible to avoid or reduce the gender bias related to this disease."

The research coordinator details this discussion by reflecting on the trajectory of Brazilians over the past 50 years. "People's life expectancy has increased significantly, and during this period, contrary to common sense, people's diet has generally improved a lot. This improvement came with more access to health, vaccination campaigns, access to drinking water, and various causes that increased human life expectancy."

According to him, these conditions influence people to become taller, stronger, larger, and more voluminous, and currently, the obesity indicator may not be keeping up with this evolution. "When we consider some typical female gender particularities, all this can enhance the bias to classify a woman as obese."

Does obesity cause other diseases?

It is no surprise that the prevalence of hypertension, diabetes, and high cholesterol is up to twice as high in obese people. PNS numbers indicate 41.5%, 13.4%, and 21.7% for the increased chance of obese individuals developing each of these diseases, respectively.

Additionally, some respiratory illnesses, such as asthma or bronchitis, are also more frequent among people considered obese (5.9%) than among people with normal weight (4.7%). The same occurs with mobility-related problems, such as arthritis and back or spine issues, which affect 11.3% and 24.9% of this population segment, respectively. However, the professor warns that this association deserves a more careful look.

"Many people often refer to it as causing other diseases, such as hypertension, diabetes, and numerous types of cancer. But obesity is not necessarily the cause of these other diseases; it is associated with them," declared Márcio, stating that the study tried to understand the following question: if obesity is associated with other diseases, what factors are associated with the occurrence of obesity in the first place?

"The inference of causality with data is always a great challenge for research. After all, what causes what? What is the cause-and-effect relationship? Factor X can cause another Y, which in turn can cause factor X. Causality can be bidirectional, and there lies the challenge of research. People usually confuse correlation, which is being related to something, and causality, in the sense of cause and effect."

Impact of diet

Although lifestyle, age, and socioeconomic issues are more relevant factors for a person to develop obesity, this study still found statistically significant differences in the consumption of some foods, such as meats, baked goods, sweets, flours and pasta, oils, and fats.

The consumption of legumes, such as beans and peas, and oilseeds, such as peanuts and nuts, is associated with lower chances of gaining weight. The probability index was calculated at approximately 4.1 and 2.7, respectively. On the other hand, the consumption of animal proteins indicates higher chances of increasing people's weight, with probabilities of 7.2 and 3.3.

"The consumption of the classic Brazilian dish, the famous rice and beans, does not pose risks of weight gain. However, another Brazilian custom, which is the barbecue, due to the consumption of red meat, is associated with significant effects on overweight and obesity, especially if associated with a lack of exercise and alcohol consumption," pointed out the researcher.

Holland adds that despite the risks for these different items, the weekly diet in the population with normal weight and the populations with overweight and obesity did not show statistically significant differences. For example, the weekly frequency with which people consume fish or natural fruit juice is quite similar among the groups defined by different BMI categories.

"It is necessary to be careful not to position foods with a higher probability of causing obesity as the main cause of it. It is necessary to associate them with the other factors brought to this discussion."

Lifestyle and factors beyond food

The association between lack of physical activity and the consumption of certain foods has been widely studied over time as an indicator of obesity. However, in addition to these physiological and metabolic issues, lifestyles and socioeconomic and demographic issues, there are other influences such as genetics, addictions like smoking and alcoholism, psychological traumas, emotional disorders, among others that are strongly associated with weight gain.

In addition to observing the lifestyles of the Brazilian population, Professor Holland believes it is necessary to observe these facts from a global perspective.

He states that some factors such as globalization and the importation of lifestyles from other cultures, especially regarding the American lifestyle, which has been embraced by Brazilians, also have an influence when it comes to obesity.

"Cultural norms such as the time spent in front of the television, especially with the rise of streaming services, allow us to observe how impressive the time people spend in front of the TV is, enhancing sedentary behavior, which is associated with weight gain. This factor can be added to these genetic and psychosocial issues, as well as possible treatments the individual has undergone, among many other factors."

Statistics and health

The researcher addresses the importance of PNS for conducting this study: "As it is a survey that evaluates the consumption profile and habits of Brazilian families, we realized that it was possible to observe eating and physical activity habits, with cuts on gender, age, among others," explained the professor.

According to him, this study was only possible because nowadays the academic community has technological tools, such as Machine Learning and Big Data, which allow analyzing large databases.

"We compared the body mass index profiles, people with normal weight, overweight, and obesity, and crossed these data with income, gender, and consumption profile of these individuals. It was from this linkage that we were able to find which factors are, in fact, closer to obesity," said Holland, emphasizing that static data do not build rules; they only indicate the variables to be analyzed.

Unprecedented study

The researcher comments that the interest in researching obesity from a multidimensional perspective arose from the fact that the causes of the disease vary greatly depending on the different countries. "As there is no common rule, there was a need for a broader vision, capable of understanding the influence of all factors and how they are statistically associated with obesity."

The World Health Organization (WHO), which warns that obesity has increased threefold worldwide since the 1970s, has been drawing attention to the importance of deepening this topic. However, most nutritionists and other health researchers investigate the possible causes only in a specific food or even in psychosocial, cultural, emotional, and even metabolic factors.

"Until then, there was no study that brought together all these factors to identify which ones were statistically most associated with the evolution of obesity here in the country. Instead of saying that a certain food can lead to weight gain, we are alerting to the numerous factors that are associated with this occurrence," declared Holland.

The researcher argues that much of the Brazilian research on the topic seeks a causative factor, instead of looking at a more integrated perspective. For him, there is no single villain but a combination of values behind the prevalence of this disease.

"If we put, for example, sugar consumption as a possible cause of obesity, it is clear that the researcher will find a high relationship. However, if we statistically observe other factors such as age, gender, physical activity, the 'sugar consumption' factor may lose importance among all these others, so it is necessary to move away from this false causality and start considering that it is not just one food that will lead to obesity, but the food system, lifestyles, urbanization, globalization, and numerous other factors."

Public policies to reduce obesity

Marcio Holland states that this project can assist managers in creating public policies based on scientific evidence. He recalls that one of the government's measures to try to reduce the incidence of obesity in the country was to tax some selected products as causes of weight gain.

"Currently, the tax on some items associated with obesity, such as sweetened beverages, is around 37% to 45%. In this research, we analyzed the effectiveness of taxing these products and sought to understand their consumption by Brazilian families. We realized the irrelevance of this type of taxation to reduce obesity, as its incidence continues to increase even after several years of high taxation."

The researcher also exemplifies that if a soda is expensive, it is likely that the consumer will replace the item with another caloric beverage. "It is necessary to think about public policies that address obesity in a multidimensional way, addressing health care, physical activity, caloric consumption, all at the same time. There is no way to separate them, as no product alone causes weight loss or gain. There are a series of factors that lead a person to gain weight."

Given this reality, the project also focused on mapping public policies for obesity worldwide, and among them, product labeling stands out. Holland points out that this type of measure corroborates the research conducted by FGV EESP, as both rely on education and awareness biases about consumption modes as a way to try to reduce obesity.

"Alerting the population about nutritional levels and weight control is important, as well as knowing the degree of overweight and, mainly, making the population aware of it. Therefore, investing in awareness through labels, having media support to inform about the topic, having public policies that prohibit certain products in schools, are examples of relevant actions as long as they are treated in an integrated, and not isolated, manner."

Investing in public policies to promote active transportation, such as bicycles and walking, improving bike lanes and sidewalks, limiting portions and types of food consumed in restaurants, are other examples that can fit into the multidimensional prevention of the disease, adopted in other countries.

For the researcher, this research is a work in constant progress, and the results found in this study open space to seek to understand even more about the factors associated with obesity to combat it more effectively.

"We are using health data from a statistical perspective to guide possible public policies and understand how to act better, reduce public spending, and the damage to the population. After all, it is better to spend on prevention than on treatments for comorbidities."

You can check the complete study here.