The causes of obesity relate to a fundamental imbalance between energy intake and energy expenditure. The World Health Organisation identified that a reduction of physical activity in combination with an increased consumption of more energy-dense, nutrient-poor foods with high levels of sugar and saturated fats, have led to obesity rates that have risen over three-fold since 1980 in some areas of North America, the United Kingdom, Eastern Europe, the Middle East, the Pacific Islands, Australasia and China.