Tag: obesity

Large Study Casts Doubt on “Fat but Fit”

New Spanish research casts doubt on the “fat but fit” paradox, where it is thought that physical fitness is enough to eliminate cardiovascular disease (CVD) risk.

Overweight and obesity is a worldwide problem that is greatly contributing to the burden of noncommunicable diseases, including CVD. A high body mass index (BMI) is strongly associated with CVD risk factors, such as hypercholesterolaemia, hypertension and diabetes. The cardiovascular complications arising from overweight and obesity are driven by processes such as inflammation, insulin resistance, endothelial dysfunction, coronary calcification. Some evidence suggested that physical activity was cardioprotective, partly or completely eliminating the CVD risk from disease – the “fat but fit” paradox.

A recent meta-analysis showed that cardiovascular fitness was a better predictor of cardiovascular disease over overweight/obesity, suggesting that perhaps public health programmes should emphasise fitness over control of body weight. To this end, the researchers sought to confirm if the “fat but fit” paradox was real.

The researchers gathered data from workers’ health insurance, with participants aged 18-64 grouped into normal weight, overweight and obesity by BMI, and into regularly active ( >150 min moderate physical activity or equivalent per week), insufficiently active (less than regularly active) and inactive (no physical activity at all). They were further separated by age, sex, smoking status and residential address.

Approximately 42%, 41%, and 18% of participants had normal weight, overweight, or obesity, respectively; 63.5%, 12.3%, and 24.2% were inactive, insufficiently active, and regularly active; and 30%, 15%, and 3% had hypercholesterolaemia, hypertension, and diabetes.

However, the protective effect of physical activity was far less than the excess risk from overweight/obesity. So much so that even regularly active obese participants had two to five-fold risk increases over their inactive but normal weight peers in the risk factors.

The protective effect of physical activity in overweight/obesity remains controversial. Shortcomings of the study were that they did not control for diet, and only accounted for self-reported leisure time activities. However, the large study size, with over 500 000 participants, should put paid to the theory that a physically active lifestyle can completely eliminate the deleterious effects of overweight/obesity.

The researchers concluded that, “weight loss per se should remain a primary target for health policies aimed at reducing CVD risk in people with overweight/obesity.”

Journal article source: European Journal of Protective Cardiology

Journal information: Pedro L Valenzuela, et al., Joint association of physical activity and body mass index with cardiovascular risk: a nationwide population-based cross-sectional study, European Journal of Preventive Cardiology, 2021;, zwaa151, https://doi.org/10.1093/eurjpc/zwaa151

Poor Diet is an Important Factor of Childhood Obesity

A Baylor University study has shown that market-bought food in addition to the traditional diet reliably predicted obesity in Amazonian children, a result that has important insights into the global childhood obesity epidemic.

Globally, 6% of girls and 8% of boys in 2016 were obese, compared to 1% in 1975. In South Africa, 13% of children under the age of five are obese.

“The importance of a poor diet versus low energy expenditure on the development of childhood obesity remains unclear,” said lead author Samuel Urlacher, PhD, of Baylor University. “Using gold-standard measures of energy expenditure, we show that relatively lean, rural forager-horticulturalist children in the Amazon spend approximately the same total number of calories each day as their much fatter peri-urban counterparts and, notably, even the same number of calories each day as children living in the industrialised United States.”

Factors such as income and access to running water were used to establish market integration. Children’s physical activity was measured with wearable devices and immune activity by measuring biomarkers obtained from minimally invasive finger-prick blood samples. Most importantly, children’s daily energy expenditure was measured with the “doubly labeled water” stable isotope-tracking method and children’s resting energy expenditure using respirometry. These are both participant-friendly, gold-standard techniques.

A third of peri-urban children were overweight, while zero rural children were, and peri-urban children on average had 65% more body fat than rural children. Peri-urban and rural children had similar levels of physical activity, and market integration, immune activity and physical activity had no effect on expenditure between rural and peri-urban children’s energy expenditure, in common with previous studies. Compared to rural children, peri-urban children spent 108 less calories while at rest, which is thought to be due to lower immune activity. Most importantly, variation in market foods was related to children’s level of body fat.

“Our findings are in line with a growing body of research pointing toward poor diet being the most important factor underlying the development of childhood obesity,” Urlacher said. “Exercise is absolutely still a critical part of this equation and is essential for living a healthy life, but diet increasingly appears to be most directly related to children’s adiposity and long-term energy balance.”

The researchers plan to follow the children longitudinally to record any development obesity and cardiovascular problems.

Source: News-Medical.Net

Weight Link to COVID Risk Emphasised by CDC

The Centers for Disease Control and Prevention (CDC) in the US has included in its coronavirus risk warning people who are considered overweight (a BMI of 25 to 29.9, obese is above 30).

Dr Donald Hensrud, director of the Mayo Clinic Healthy Living Program, explained that obesity already is associated with several complications – diabetes, high blood pressure, dyslipidaemia and cardiovascular disease.

Dr Hensrud said, “Now COVID-19 comes along, and we’ve got all the issues we had before plus some additional ones. Obesity is associated with low-grade inflammation and an effect on our immune system. This affects our susceptibility to COVID-19. People who are obese are more likely to develop COVID-19 and complications from it, including dying, than people who aren’t obese. In addition, people with diabetes and some of the other complications from obesity are also at increased risk. So obesity and its complications independently take the risks of COVID-19 and elevate them significantly.”

Dr Hensrud said that he noted patients of his had put on weight during lockdown due to comfort eating and staying at home without any exercise. In order to reduce their risk, people should resolve to eat a healthy diet and engage in exercise, although he cautioned that losing more than 10% body weight in six months can impact the immune system.

Source: Medical Xpress