1 month old This article is more than 1 month old Obesity could soon overtake smoking as the main preventable cancer risk People take part in an exercise class at a Nuffield gym in Sunbury-on-Thames, west of London, pre-lockdown in July 2020. Photograph: Adrian Dennis/AFP/Getty Images People take part in an exercise class at a Nuffield gym in Sunbury-on-Thames, west of London, pre-lockdown in July 2020. Photograph: Adrian Dennis/AFP/Getty Images Sun 14 Feb 2021 02.15 EST Taking regular exercise is going to become increasingly important in helping to prevent cancers as the UK emerges from lockdown, say scientists. Since the pandemic began a year ago, growing numbers of people have reported gaining weight after cutting down on physical activity while others say they have been eating more junk food.