I'm considering getting some food containers, but I noticed most of them have this in the description:

Not suitable for foods with a high fat or sugar content

Why is that ? What could happen if I stored some, say, chicken fat - or plain sugar - in one of those ? They're microwave and freezer safe, so how come they can't handle fat or sugar ?

In addition, are there any rules of thumb for determining which foods have a high fat or sugar content ? It's not always obvious. For example, a dish having 1/3 mince meat - would it be high on fat - and therefore unsuited for the container ?

2 Answers 2


The best reason I can come up with is that microwaving items with oil and/or fat can lead to temperatures much higher than the 90C maximum that is recommended.

From the link:

  • Microwave, dishwasher and freezer safe
  • Suitable for temperatures up to 90c
  • Not suitable for foods with a high fat or sugar content
  • That would be my assumption, too ... fats, sugar and water absorb microwaves much faster than other ingredients ... water can't get to as high of a temperature, though.
    – Joe
    Commented Oct 18, 2015 at 22:54
  • @Joe: It's not that they absorb microwaves faster - quite the opposite: water absorbs microwave faster so low fat food should heat up faster. It's that they can go to a higher temperature when heated. Water for example can never go above 100 degrees C when heated in an open container (at sea level) without turning to steam. So you can do tricks like boil water in paper containers without burning the paper because the water prevents the paper from getting hot enough to burn. But fats can get to very high temperatures.
    – slebetman
    Commented Oct 19, 2015 at 4:11
  • 1
    just to add some product info, i found out that many food containers from "that swedish furniture store"® are able to hold any fats / sugars for heating. the 365+ one (and many similar from other brands and stores) offer a valve that you can "open" when heating those types of meals so it doesn't overheat.
    – CptEric
    Commented Oct 19, 2015 at 6:31
  • 1
    My food container got damaged in microwave due to fat, it got inside plastic (its from spaghetti sauce, so it is quite visible). I can shot a photo later today if you want.
    – PTwr
    Commented Oct 19, 2015 at 6:45

Although I am not an employee in the product development department of companies that make products labelled like this, I do have empirical experience with a product labelled as you describe.

When fat is present in a microwave and in contact with the container, the product's surface can deform in a way that retains food and thus poses a health risk. This can happen with a sauce that has just a little bit of fat floating on top. The product manager must ensure you do not buy this product if you have fat in your diet and are looking for something to use when reheating food as part of your lifestyle and thus they have labelled it to protect you from making an incorrect purchase. I justify this as the likely reason with an anecdote:

I once reheated food in such a container with a sauce that had a little bit of fat floating on it (maybe a tablespoon's worth). The plastic deformed where the fat was floating and did so in a way that it was no longer safe to use because of the risk of bacterial growth.

I think that is why they add a such a label and that is what could happen.

  • "they have labelled it to protect you from making an incorrect purchase" - of course such labels rarely work in this situation. The product manager wants you to buy it, throw it away and keep quiet so other people do the same and I am certain this is the actual reason but I suspect I'm not allow to put a conspiracy theory into an answer here so I've relegated that bit to this comment.
    – codeshot
    Commented Oct 25, 2015 at 10:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.