Large numbers of fast food restaurants in an area can push up the stroke risk by up to 13 per cent, researchers found. The findings were released as another study showed that having an unhealthy lifestyle, including drinking too much, eating unhealthily, smoking and shunning exercise, can more than double the risk. Strokes are the third biggest killer in Britain, after cancer and heart disease. More than 150,000 people have a stroke every year in this country, of whom about 67,000 die. Researchers found that a single fast food outlet could increase the stroke risk for an area by one per cent. The study, by the University of Michigan, compared the number of strokes in different parts of Nueces County, Texas, home to 262 fast food restaurants.