Research of a hunter gatherer tribe in Tanzania has revealed that the amount of calories we need is a fixed human characteristic.

The anthropological research has applications for how westerners perceive weight loss, revealing that the notion of exercise being more important than diet in the fight against obesity is a misnomer. It also shows that the obesity epidemic in the Western world is caused by over-eating rather than having inactive lifestyles, say scientists.

One in ten people are expected to be obese by 2015, and one in three of the worldwide population is expected to be overweight. Figures from the World Health Organisation have pointed towards an obesity epidemic in the west.

The Hadza people, who still live as hunter gatherers, were used as a model of the ancient human lifestyle. The tribe hunt animals and forage berries, roots and fruit as their staple diet, in comparison to the west, where processed foods high in sugar and fat, large portion sizes, and a sedentary lifestyle is the norm.

Dr Herman Pontzer of the department of anthropology at Hunter College, New York, said: “This to me says that the big reason that Westerners are getting fat is because we eat too much – it’s not because we exercise too little.

“Being active is really important to your health but it won’t keep you thin – we need to eat less to do that. Daily energy expenditure might be an evolved trait that has been shaped by evolution and is common among all people and not some simple reflection of our diverse lifestyles.”

A rent study was carried out by researchers from VU University Medical Centre, Amsterdam, and other institutions in The Netherlands found that two-thirds of obese children show early signs of heart disease. Most of the children studied showed risk factors for CVD that you would normally only expect to see in older adults, such as high blood pressure and high blood glucose levels.