MNT featured. The number of overweight schoolchildren in the UK is almost two million, of which about 700,000 are obese, according to a study carried out by the International Obesity Taskforce.Over 25% of girls and 20% of boys are overweight.The number of UK schoolchildren who have high blood pressure and cholesterol levels has reached 160,000. If this trend towards more obese and overweight children continues, the UK could be facing a serious national health crisis in a decade's time, say researchers.ver 25% of girls and 20% of boys are overweight. The number of UK schoolchildren who have high blood pressure and cholesterol levels has reached 160,000. If this trend towards more obese and overweight children continues, the UK could be facing a serious national health crisis in a decade's time, say researchers.