Obesity and less activity
Less frequent physical activity is not likely to be the main reason for obesity in the western world, suggesting that too much calories is the biggest factor.
Some researchers have suggested that the differences between Western lifestyles and the more active lifestyles of our hunter-gatherer ancestors may explain why obesity rates have shot up in some parts of the world over the past few decades.
American, British and Tanzanian researchers have carried out a study that examined the total energy expenditure (TEE) of the Northern Tanzanian Hadza tribe of hunter-gatherers.
They theorised that the hunter-gatherers would use up more energy in their regular activities than those in market and farming areas but that was not what they discovered.
The research team said: “Contrary to expectations, measures of TEE among Hadza adults were similar to those in Western populations”.
They discovered that the Hadza community had higher levels of physical activity, but after controlling for body size and composition, their energy expenditure was statistically indistinguishable from that of Westerners.
As their results concluded, energy expenditure may have a small part in judging whether someone will become overweight or not with a more complex metabolic strategy at work to respond to energy availability and demand.
In other words, the most essential cause of obesity is likely to be eating too much rather than doing too little.
The research team added: “The similarity in TEE among Hadza hunter-gatherers and Westerners suggests that even dramatic differences in lifestyle may have a negligible effect on TEE, and is consistent with the view that differences in obesity prevalence between populations result primarily from differences in energy intake rather than expenditure”.
However, the researchers did mention that increased physical activity does have health benefits.
The researchers continued: “Physical activity has important, positive effects on health, and increased physical activity has been shown to play an important role in weight loss and weight-maintenance programs.
“Some studies of self-reported activity level have even suggested that habitual activity may help prevent unhealthy weight gain, although the evidence is mixed”.