If your little one starts school next year, you have probably already fallen down the lunch box rabbit hole. So many sizes, so many compartments, and somehow every one of them is "the best".

Here is the shortcut I give every parent who asks: forget the features for a minute and think about how much your child actually eats. That one answer picks the lunch box for you.

Big eater? Go for the b.box Original. Smaller appetite? The b.box Mini. And either way, add a separate snackbox for that first little break of the day. Here is why.

Big appetite? The b.box Original lunchbox (with inserts)

If your child clears their plate and asks what's next, the b.box Original lunchbox is the one. It was designed to fit whole pieces of fruit and a whole crusts-on sandwich, so there is no cutting everything into tiny pieces at 7am.

What you get in the one box:

• A large compartment that fits a whole sandwich, roll or wrap
• A whole fruit holder with a stretchy seal, so the apple or mandarin goes in as is
• Two leakproof compartments for wet foods like yoghurt, custard and dips
• A removable divider, so you can change the layout to suit what you are packing
• A gel cooler pack that sits under the sandwich tray to help keep food cooler for longer
• Handles and a big grip clip that little hands can open on their own

The bit that makes it work for a big eater is the inserts. They let you pack more variety without everything rolling into one corner:

• Bento buddy - lunch: a silicone insert that splits the space into sections. A lifesaver if your child hates foods touching.
• Lunch tub: a 400ml lidded tub that fits the sandwich compartment. Great for leftovers, pasta or salad on the days a sandwich won't cut it.
• Silicone snack cups: keep small snacks separate and in place.
• Feast tray: sold separately, for the grazers who like lots of little bits.

You can also lift the sandwich tray out altogether for deeper lunches like big rolls, scrolls or pasta. One thing to know: the Original is hand wash, and it is freezer safe.

Smaller appetite? The b.box Mini lunchbox

If lunch boxes usually come home half full, don't size up "just in case". Go for the b.box Mini. It is smaller and lighter to carry, but it still fits lots of food.

The Mini is my top pick for my own boys' lunch boxes. It is a smaller version of the Original with the same clever bits:

• The same stretchy whole fruit holder
• A long compartment that fits a crusts-on sandwich cut in half
• Two leakproof compartments for yoghurt, puree and dips
• A slide-and-glide divider you can move or remove
• A carry handle and easy-open grip clip
• 1 litre capacity, in a compact size that fits inside a b.box lunch bag

A school bag is already big on a five year old. A lighter lunch box makes a real difference when they are also carrying a drink bottle, a hat, a jumper and a library bag.

A smaller box also looks less overwhelming when they open it. Kids with small appetites often eat more when there is less in front of them.

Want more variety in the Mini? Add the bento tray for the Mini or a set of silicone snack cups.

Don't forget the snackbox for munch and crunch

Munch and crunch, brain break, fruit break, crunch and sip. Whatever your school calls it, most classes stop for a quick fruit or veggie snack before the first proper break.

This is where a separate b.box snackbox earns its spot in the school bag. Whichever lunch box you choose, I would add one.

• Your child grabs one small box, not the whole lunch box
• The rest of their lunch stays closed, cool and uneaten until lunchtime
• There is no digging past the sandwich to find the fruit while the class waits

The snackbox has two compartments with that same stretchy seal. You can pack small whole fruit next to yoghurt or dip without leaks. The clip is easy for little hands, it is freezer safe, and it is dishwasher safe on the top rack.

Pair it with a snack buddy (the bento buddy - snack). It is a silicone tray that sits inside the snackbox and keeps foods apart. Think cheese and crackers without the soggy crackers, or cut-up veggies next to berries.

The snackbox fits alongside a lunch box in a b.box lunch bag, so it all travels together.

A few extras worth adding

You don't need all of these. Pick the ones that suit what your child actually eats.

• Sandwich lover? Add a b.box silicone lunch pocket. It is a reusable pocket that keeps a sandwich or wrap fresh and together, so there is no cling wrap to peel off or throw away.
• Might want hot food? Add an insulated food jar. It keeps hot foods warm and cold foods chilled, so leftover pasta, fried rice or soup can go to school on cooler days. The mini 200ml and 230ml jars fit inside the b.box Original.
• Pack a fork and spoon set too. Kid-sized cutlery made to fit in a lunch box means no sticky fingers, and no borrowing from the tuckshop.
• Finish with an insulated lunch bag. The b.box insulated lunch bag has flexible sides and keeps food cooler for longer. If you want something smaller, the Sachi junior lunch bag fits the Original, the Mini and the snackbox.

Tip: if you are packing hot food, warm the jar with boiling water for a few minutes first, then tip it out and add the food. Practise opening the jar at home too, as the lids can be tricky for little hands at first.

Quick guide: which one is right for your child?

Still not sure? Think about what comes home from kindy or daycare now. If the lunch box is usually empty and they are still hungry at pick up, choose the Original. If there are always leftovers, choose the Mini.

A few tips before day one

• Practise over the holidays. Pack lunch in the new lunch box for park trips and beach days. By the first day, your child can open and close it without help.
• Start smaller than you think. The first few weeks are busy and exciting, and lots of kids eat less. You can always add more.
• Label everything. Lunch box, snackbox, inserts and lids.
• Ask what the school calls snack time. Use the same name at home so your child knows which box to grab.

Starting school is a big step for them and for you. The lunch box is one thing you can tick off early. Pick the size that suits your child's appetite, add a snackbox, and you are sorted.