Hunter gatherer clue to obesity

[xchrom]

http://www.bbc.co.uk/news/science-environment-18985141



The Hadza live a hunter gatherer existence that has changed little in 10,000 years

***SNIP

Diverse lifestyles
A team of scientists from the US, Tanzania and the UK, measured energy expenditure in 30 Hadza men and women aged between 18 and 75.


They found physical activity levels were much higher in the Hadza men and women, but when corrected for size and weight, their metabolic rate was no different to that of Westerners.

Dr Herman Pontzer of the department of anthropology at Hunter College, New York, said everyone had assumed that hunter gatherers would burn hundreds more calories a day than adults in the US and Europe.

The data came as a surprise, he said, highlighting the complexity of energy expenditure.

[salvorhardin]

1. This article makes no sense

If the Hadza have much higher activity levels, they must be expending more energy, thus burning more calories. If the body can't get the calories from serum glucose, then it taps into fat reserves. If it can't tap fat reserves, then it starts cannibalizing muscle tissues. The energy has to come from somewhere. I just don't see how a sedentary office worker could expend the same amount of energy as an active hunter-gatherer of the same size and weight.

[Viva_La_Revolution]

2. Here's the actual paper..

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0040503

and the crux
Our results indicate that active, “traditional” lifestyles may not protect against obesity if diets change to promote increased caloric consumption. Thus, efforts to supplement diets of healthy populations in developing regions must avoid inundating these individuals with highly-processed, energy-dense but nutrient-poor foods. Since energy throughput in these populations is unlikely to burn the extra calories provided, such efforts may unintentionally increase the incidence of excess adiposity and associated metabolic complications such as insulin resistance. Indeed, processed, energy-dense foods have been linked to insulin resistance and cardiovascular disease among Australian foragers transitioning to village life [41].

[bemildred]

3. Yep, I agree.

The whole "corrected for size and weight" idea bothers me, and aside from that the relation between physical size and work done for the same activity is non-linear, and it is not correct that metabolic rates of the small and the large should be the same.

I would expect hunter-gatherers, who live at a subsistence level in a hazardous world, to be parsimonious in their expenditures of calories; it is we who can afford a "high-energy" lifestyle.