South Africa has the highest overweight and obesity rate in sub-Saharan Africa, with up to 70% of women and a third of men being classified as overweight or obese, according to the Heart and Stroke foundation of South Africa.
Now more evidence links poor sleep and excess weight: A new study by the University of Glasgow found that people who are genetically prone to obesity are more likely to be overweight if they have unusual sleep habits.
"These data show that in people with high genetic risk for obesity, sleeping for too short or too long a time, napping during the day, and shift work appears to have a fairly substantial adverse influence on body weight," said researcher Dr Jason Gill of the University of Glasgow, Scotland.
Insomnia boosts obesity risk
Gill, who is with the university's Institute of Cardiovascular and Medical Sciences, looked at statistics on nearly 120 000 people in the United Kingdom.
The investigators said they found that sleeping fewer than seven hours a night or more than nine hours a night boosts the risk of obesity among those who are especially prone to it because of their genes.
Among those with a genetic propensity toward obesity, those who slept more than nine hours a night were almost 4kg heavier than similar people who slept seven to nine hours. Meanwhile, those who slept less than seven hours were a little more than 1.8kg heavier than their better-rested peers, the findings showed.
Although the study doesn't establish a direct cause-and-effect relationship, the researchers found this effect persisted regardless of diet, health problems or income level.
"However, the influence of adverse sleep characteristics on body weight is much smaller in those with low genetic obesity risk – these people appear to be able to get away with poorer sleep habits to some extent," Gill said in a university news release.
State of obesity in SA
“There are many reasons as to why we are facing this obesity epidemic,” says Dr Vash Mungal-Singh, CEO of the Heart and Stroke Foundation of South Africa (HSF). “It is difficult to pinpoint one culprit but people need to understand that our lifestyles are largely to blame. South Africans eat too much, drink too much alcohol, and don’t move enough,” she adds.
“We need to educate the South African public about the risks of an unhealthy lifestyle and being overweight. If the public does not believe that they need to eat healthier and exercise more, any strategies that address these issues will be unsuccessful,” says Gabriel Eksteen, Registered Dietitian at the HSF.