An oversupply of food is the reason for burgeoning obesity rather than inactive lifestyles - a new study suggests. File Photo: Finbarr O'Reilly

Cape Town - An oversupply of food, which encourages overeating, is the reason for burgeoning obesity rather than inactive lifestyles, a new study suggests.

The study, based on outcomes of various other studies over a 40-year period in 69 countries looked at associations between changes in food supply in different countries in relation to population body weight, and found that increases in food supply in individual countries translated to increase in body weight.

The study, which appears in the latest Bulletin for the World Health Organisation (WHO), also found that high income countries were more likely to experience obesity compared to low income countries due to an oversupply of food.

Researchers found that in 80 percent, or 45 countries, the increase in food supply was more than sufficient to explain the increase in body weight of citizens. This pattern was observed in countries of all income levels.

About five countries that experienced reductions in food supply also experienced a decrease in average body weight.

However, in three countries - South Africa, Iran and Rwanda - there were discordant changes in the other direction with increases in food supply translating in reductions in average body weight.

Lead researcher Stefanie Vandevijvere, from the University of Auckland in New Zealand, said while physical activity might also lead to obesity and could occur simultaneously with an increase in food supply, research at country level such as the US had shown that physical activity had only a very small impact on obesity prevalence.

“A reduction in physical activity with no compensatory drop in energy intake will cause weight gain until sufficient weight is gained to create energy balance through an increased resting metabolic rate,” he said.

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Cape Argus