According to the new study, kids who are overweight shows signs of heart disease when they reach 15 years old.

Obese children aged between 9 to 12 years old has higher probability of showing risk factors such as high cholesterol and high blood pressure when they reach age 15 to 16.

The study investigated more than 50,000 children and measured their blood pressure; insulin levels glucose and insulin levels. The study was conducted by researchers at University of Bristol.

Beginning of the study when the kids were aged 9 to 12, 19% of the samples were overweight and another 5% were obese.

"Girls who favourably alter their overweight status between childhood and adolescence have cardiovascular risk profiles broadly similar to those who were normal weight at both time points," the researcher said.

"But boys who change from overweight to normal show risk factor profiles intermediate between the normal at both ages and overweight at both ages."

The researchers discovered a high body fat mass and big waist circumference was also correlated to boosted risk, regardless of BMI.

The research was published in the British Medical Journal.