What happened when some Aboriginal Australians temporarily returned to a traditional hunter-gatherer lifestyle?

Details

This review examined published data on the impact of westernisation on obesity, non-insulin dependent diabetes mellitus (NIDDM) and coronary heart disease (CHD) among Aboriginal Australians. It cited 55 articles from Australian and international sources, primarily peer-reviewed journals. Of these, 28 reports provided data on Aboriginal Australians’ diet, lifestyle, health and ‘lifestyle diseases’ before and after westernisation. Another 27 articles on obesity, NIDDM, CHD, insulin resistance, and the effects of diet and exercise helped interpret the Aboriginal data. The review used information on dietary composition, body measurements, disease and risk-factor prevalence, and relevant biochemical measurements for comparison and interpretation.

The authors reported that the traditional hunter-gatherer lifestyle, with high physical activity and a low-energy-density diet low in fat and high in fibre, promoted a very lean body weight and minimised insulin resistance. In contrast, they described a Western lifestyle for most Aboriginal Australians as involving less physical activity and an energy-dense diet high in refined carbohydrate and fat, promoting obesity and maximising insulin resistance. They reported high prevalence of obesity with an android pattern of fat distribution, NIDDM, impaired glucose tolerance, hypertriglyceridaemia, hypertension and hyperinsulinaemia following the transition to a westernised lifestyle.

A temporary return to a traditional hunter-gatherer lifestyle was followed by striking improvements in carbohydrate and lipid metabolism among Aboriginal Australians both with and without diabetes. The authors said this highlighted the potentially reversible nature of the harmful effects of lifestyle change, particularly in young people who had not yet developed diabetes. They suggested that insulin resistance was important for survival as hunter-gatherers but was also an underlying metabolic characteristic predisposing Aboriginal Australians to obesity, NIDDM and CHD after westernisation. They recommended lifestyle modification to prevent chronic diseases related to insulin resistance. They concluded that effective programmes would need to be developed and implemented at the community level.