If one of your New Year resolutions is to lose weight, here's some important news for those of you still sold on the idea that calories make you put on the pounds. Researchers in Nairobi, Kenya have reported an explosion in obesity levels among the urban poor in sub-Saharan Africa. Numbers of obese and overweight people have increased by 35 per cent between 1990 and 2000. And it's not because they are eating too much food - they can't afford to do so - it's because they are eating cheap, processed foods that are high in complex carbohydrates. In other words, it's not just the amount you eat, it's what you eat that makes a difference to your weight. (Source: BMC Public Health, 2009; 9: 460).