Nearly a third of 11 year olds in Jersey are overweight or obese.
3 in 5 over 45s also fall into those categories.
The latest data of height and weight measurements of children starting and leaving primary school shows 2 in 10 Reception-aged children are overweight or obese.
That rises to 3 in 10 Year 6 pupils, by which time more boys than girls are above a healthy weight.
One in six adults are obese. There has been little improvement in that figure in the past decade.
Only a quarter of 11 year olds get the recommended hour a day of exercise, and only half of adults do at least 2.5 hours a week of physical activity.
Statistics Jersey's Obesity, Diet and Physical Activity Profile includes data from a number of different sources.
It also suggests:
*Two-fifths of 16-34 year olds are classed as overweight (Body Mass Index of 25-30) or obese (BMI 30+), compared to almost three-fifths of people aged over 45.
*Just over a third of adults eat 5 portions of fruit or veg a day.
*46% of boys and 33% of girls in Year 6 spend three hours or more a day on electronic screens. That rises to more than 70% of children in Year 10.

£75,500 raised in Jersey Christmas Appeal Charity Auction
Government to announce support option for carers
Drink driving can cause 'life-changing' consequences
Parked cars damaged in Victoria Avenue crash
L'Ecume II: Lewis Carr jailed for 20 months for fatal collision at sea
Guernsey's former Chief Minister admits making indecent images of children
Minister approves 42 sheltered homes at nursing home
Jersey potato farm to be the site of Channel Islands' largest roof solar array