IF YOU’RE INACTIVE
You need about 120 kilojoules per kilogram of bodyweight. For a 68-kilogram woman, that’s about 8100 kilojoules a day; for an 80-kilogram man, it’s about 9600 kilojoules a day.
IF YOU’RE SLIGHTLY ACTIVE
(Fewer than three exercise sessions a week, but regularly on your feet and moving about.) You need about 130 kilojoules per kilogram to maintain your weight. For a 68-kilogram woman, that’s about 8850 kilojoules; for an 80-kilogram man, it’s about 10,400 kilojoules.
IF YOU’RE ACTIVE
(Getting 30 to 60 minutes of exercise at least three times weekly.) You need about 140 kilojoules per kilogram of body weight. For a 68-kilogram woman, about 9500 kilojoules; for an 80-kilogram man, about 11,200 kilojoules.
To lose about 200 grams a week – a realistic, goal for people who make small healthy lifestyle changes – you need 1050 kilojoules less per day. It’s easy to eat 525 fewer kilojoules by, for example, having fruit instead of ice-cream.It’s just as easy to add 525 kilojoules of exercise with a 15-minute stroll at lunch and another after dinner.
Or you could wash the car, rake leaves and use the stairs instead of the lift.