Lunch Momming in the 6ix School

Choosing Lunch Containers for School – Stainless Steel vs Plastic

June 1, 2023
Stainless steel lunch containers on picnic table

If you’re in the market for bento-style lunchbox I’ll be breaking down two common materials that I’ve researched and used. Now full disclosure, my preference is always stainless steel but I think there is a practicality that plastic offers.

Choosing between Plastic vs Stainless

“Safer” or Safest Materials

Tritan is a considered a safe, high quality plastic that is BPA free. You’ll find this material with both YumBox and Munchbox. With Tritan it is a man-made material and end of the day, still plastic. Combine that with a plastic/silicone lid, you’ll have to be diligent about cleaning the outer lid and ensuring that overtime that mold is not hiding in any of the crevices. There are other plastic options like the OmieBox which is made if a different style plastic and has a removable silicone seal so you can do a deeper clean, and replace when needed.

Food grade stainless steel like 18/8 or 304 stainless steel is considered one of the safest materials following glass. The steel is non-porous, easy to clean, and basically will last a lifetime.

I won’t be discussing glass at this time since it’s not practical for young children.

Yumbox now offers the Presto which is a mix between having a stainless steel tray and plastic/silicone lid. Now I like the idea that the food only touches stainless steel and silicone – but you may still run into the issue of a moldy lid over time.


This will vary by which container you choose. But stainless steel can be potentially quite heavy. If you’re shopping in store, note how heavy these containers feel empty – once you fill it up with food or other leakproof containers, they will add more weight.

From what we’ve seen with most full sized bento boxes – they all weight about the same at 1 lb.

Weight might not be a very important factor if they live close to school, don’t carry much, etc. But if your child has to carry it for a while – it could be quite heavy, even for adults alike.

Ease of use

Generally speaking plastic containers might offer more variety in terms of how these bento-style boxes can be opened and closed. If you’re shopping for a young child, their ability to open and close containers is probably the most important factor. Now teachers and other supervisors will most likely help out your child if they have trouble, but do practice at home with your containers so that your little one doesn’t have to wait on help and can spend more time finishing their meal.

Another advantage to plastic is that they can be potentially more leakproof than stainless steel options.


Visually plastic looks more exciting to both children and adult eyes. The colours, the patterns and design can really catch their attention. My son overall loved looking at the graphics within the tray and it made him excited about what to fill it with.

Your child might have strong opinions on what they want as well. It might come down to what they end up choosing and asking for.

We love PlanetBox since they have a creative way to make stainless steel fun, by offering customizable magnets, colourful pods (sold separately) and leak proof containers that have colourful silicone lids. Other stainless steel bentos may feature other colourful silicone sleeves or lids. But depending on the child, not all lids are easy to open and may be better suited for an older child.

Leak Proof / Staying Mess Free.

For the the most part if a brand says the containers are leak-proof, it should be pretty solid from getting from your house to the lunchroom. One thing to consider is how these containers may hold up on the way back home when your child packs it back up together. The ability to easily and securely close the container may be an important factor. For the I do like the plastic containers with easy to use latches. But for lids that require a child to carefully press all 4 sides down securely, you might end up with a mess on the way home if there are left overs.

A note on glass

Glass is probably hands down the most safe material but it’s also very impractical if you’re on the go. I wouldn’t even recommend this for older kids because their backpacks are already so heavy with textbooks, laptops, gym clothes etc.

As an adult, glass is great because you can reheat your lunch. But if you’re commuting to work, glass can be too much weight as well.

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