How many kJ does the average person need?

The simple fact is, everyone is different. The number of kJ needed every day to maintain a healthy weight depends on a number of factors. Age, height, your sex and level of physical activity all influence what is the ideal 'healthy' weight range for you.

To give you an idea of how many kJ some 'average' people consume and burn in a typical day, let's meet a few.

  • Brooke - The Office worker

    The Officeworker

  • Tom - The Tradie

    The Tradie

  • Jack - The growing boy

    The growing boy

  • Erin - The teenager

    The teenager

  • The Office worker

    This is Brooke. She's 26, has a job she loves working in a financial planning company and she's reasonably conscious of what she eats. While she's fairly active outside of work, she would hardly call herself a gym junkie.

    Brooke would call herself a 'healthy eater who indulges in the odd treat'. So let's have a look at what she ate yesterday.

    A Breakfast of fruit muesli (50g), skim milk (50ml) and a small skinny cap (150ml).

    She was too busy to stop for a morning snack so she didn't eat again until lunch.

    Lunch was a medium Pesto Chicken & Avocado Salad (200g) and a diet cola (330ml).

    Around 3ish she had a snack of a small chocolate bar (75g) and a cup of tea with a splash of milk.

    And finally for Dinner, her favourite, Spaghetti Bolognaise (200g) and a glass of red wine (150ml), topped off with dessert of a small bowl of ice cream (45g).

    All in all, a pretty normal day. Certainly nothing that she'd call 'over indulgent'.

    So it might surprise her (and you) to know that this 'pretty normal day' yielded over 9,500 kJ.

    Remembering that Brooke has a job where she's not particularly active during the day, she may be taking in more kJ than her body actually needs to maintain a healthy weight.

  • The Tradie

    Meet Tom. He's 35 and has his own building company. While he hasn't completely given up the tools, these days he spends less time on site than he once did. Some days he'll be flat doing his share of the work that goes into building a house. Other days he'll spend more time on the paper work and getting things organised.

    Tom's work-day normally sees him on site by 6.30am. He works hard and doesn't like spending too much time away from the job, so his food choices during the day are based around what's quick, easy and filling.

    Breakfast is usually on the run at one from one of the larger 'fast' and snack food chains he finds on the while driving to the job. He'll usually grab a sausage and egg muffin and a large flat white coffee.

    Morning Tea is a banana he's bought from home.

    Lunch needs to be filling and a Chicken & Mayo wrap, a regular serve of chips and a can of soft drink (375ml) normally see's him though to dinner.

    For Dinner tonight it's something quick and easy; 3 good Pork sausages, 2 generous scoops of mashed potato, gravy and peas with a couple of glasses of beer.

    All up, Tom's food choices for today added up to just over 10,000 kJ.

    And while there's no doubt that when he's doing the hard, physical work his job sometimes demands, his body will probably use all that energy. On other days when he's not as active, he could be taking in more than what he needs to maintain a healthy weight. Remember, we're just talking here about the energy in Tom’s food, not whether it's healthy as a regular eating pattern!

  • The growing boy

    This is Jack. He's in Grade 4 at the local primary school and like a lot of kids his age he rarely sits still. Footy, cricket, riding his bike, he loves them all, but he still finds time to sit in front of the TV playing video games.

    Nicole, Jack's mum, is really conscious of what he eats so she makes sure he gets a good even spread of fruit, veggies, eggs, rice and pasta. He's not too keen on meat at this stage but he's starting to try a few different things.

    So let's have a look at what he might eat on a fairly normal sort of day.

    Breakfast. It's Sunday morning so Jack gets to have his favourite, scrambled eggs on toast and orange juice (he picks his favourite when they go shopping at the supermarket).

    Sunday is soccer with the local under 10's, so for a Mid Morning Snack Nicole gives him a fruit bar to see him through til lunch.

    Lunch is pretty simple – a cheese and vegemite sandwich on soft white bread and a little packet of sultanas. And around 3ish, he has an apple.

    And for Dinner tonight everyone's having baked risotto and ice-cream for dessert.

    For Jack, his kJ intake on this day was a little over 4,200.

  • The teenager

    Erin is a fairly typical teenage girl. She's in Year 11 at Secondary school and hopes to go on to uni after Year 12, so homework is starting to take up more time than it used to. She does a bit of sports at school and plays netball on the weekends. She loves hanging out with her friends and she spends a bit of time online.

    Let's look at what Erin might eat on a fairly normal school day.

    Breakfast. Erin has 2 pieces of raisin toast and butter and a glass of freshly squeezed orange juice.

    For a Mid Morning Snack she grabs a processed fruit strip snack, they're easy and she really loves the taste.

    Lunch is a Sausage roll with a little tomato sauce and an apple juice from the school canteen. And she grabs a banana muffin for a mid arvo snack.

    When she gets home from school she'll have a couple of chocolate biscuits and for Dinner tonight is a beef stir fry with lots of veggies.

    So today Erin's food choices added up to just on 8,000 kJ.