Jenny Dunn is head of Seymour Park primary, a 600-place school in Trafford, Greater Manchester: "I have seen a very real decline in children's general fitness in recent years. I don't know if it is because they are more sedentary and watch more television, but they don't seem to play around outside as much as we did in my generation.
"Even the parks are unsafe, so there's nowhere for them to go.
"Another health concern is dental care. According to the Dental Health Service, a mixture of poor diet and lack of dental care is leading to problems in children's teeth in the Greater Manchester area."
Sue Roberts, head of the lower school at Prendergast school for girls, in Lewisham, south London, says the main problem among the 640 pupils is eating disorders.
"Weight is an issue that girls seem to be taking increasingly seriously. At Prendergast, under-eating in the form of bulimia or anorexia is on the rise. I would say that between 60 and 70 per cent of the 330 girls in Years 7, 8 and 9 seriously consider everything they eat. Since the problem is on the increase we are now having staff training so that we all share information and know how to deal with it."
Stewart Thomas, headteacher of Acland Burghley, a 1,230-pupil comprehensive in Camden, north London, feels that the food offered to children is often not conducive to healthy living.
"For kids to be healthy, they need to eat well. In too many schools, the daily diet consists of chips, hamburgers and pizzas - fast food that is instantly gratifying. I really believe that a better food policy needs to be implemented in schools so that there is more emphasis on what is nutritionally good for them."