Glass vs. Plastic: Choosing the Best Meal Prep Containers

If you're about to make even a small investment in kitchen storage and meal prep containers, the debate between which is better—glass or plastic—probably has landed squarely on your table.

So get ready for a little “kitchen chemistry.” Just like when you learned why yeast must “proof,” why shortening produces different results than butter in baked goods, and why extra virgin olive reigns supreme, your eyes might roll as easily as a turkey meatball off a spoon. It might help to think of this as a painless and short-term condition that, in the end, will help you make an informed and educated decision about glass vs. plastic.

But here's a pointer to ponder: Think about which type of person you are—the type who is content to plunk down an open bag of almonds on a table or the type who empties the almonds in a bowl. If you're the latter—careful and somewhat fussy—then you're likely to invest in glass meal prep containers.

Choosing between glass and plastic meal prep containers is like a three-step recipe. It calls for you to add a dash of science, whisk in your opinion of the controversy (yes, controversy) and then leaven your final decision with the word “fastidious.” It either describes your basic nature—and how you “dress” your table—or not.


Weigh the science of plastic

Tupperware might be the best-known manufacturer of plastic containers, but it certainly isn't the only one. Many plastic food containers are made with polycarbonate, which the company describes as “a high-strength plastic made from a monomer known as bisphenol-A (BPA).”

The straight-talking scientists at the American Chemistry Council deftly explain the appeal of this storage choice when they point out that “airtight polycarbonate food storage containers help preserve freshness and protect foods from contamination, and many polycarbonate food containers offer the added convenience of safely going from freezer to microwave to dishwasher.”

Plastics are categorized based on which raw material was used in their production. They are classified by one of seven resin identification codes, numbered 1 through 7. You can find this code imprinted in a small triangle on the bottom of all plastic containers. The seven categories are:

  •  Category 1: Polyethylene terephthalate ethylene, which is used to make juice, peanut butter, soft drink and water containers.
  • Category 2: High-density polyethylene, which is common in water and milk jugs as well as shampoo and detergent containers.
  • Category 3: Polyvinyl chloride, which is used to package peanut butter and cooking oil and also detergent and window cleaner.
  • Category 4: Low-density polyethylene, which is found in grocery store bags, most plastic wraps and some bottles.
  • Category 5: Polypropylene, which is used in straws and other clouded plastic containers as well as yogurt and syrup containers.
  • Category 6: Polystyrene, which you will find in egg cartons, Styrofoam food trays, disposable cups and bowls and carryout containers.
  • Category 7: Usually polycarbonate, found most often in baby bottles, sports water bottles, some plastic cutlery and some name-brand food storage containers.

Regulatory authorities weigh in

The Academy of Nutrition and Dietetics doesn't mince words: “In general, the safest choices for food use are numbers 1, 2, 4 and 5,” it says. That's good news for many consumers because many leading plastic containers are made from No. 4 or 5 plastics. But it has placed Tupperware in particular under the spotlight, because many of its containers are made with polycarbonate (and its derivative, BPA), a category 7 plastic.

How much of a health risk, if any, this plastic poses has been the focus of intense study, scrutiny and debate by government agencies, academia and regulatory authorities worldwide. The fear is that trace levels of the hormone-disrupting BPA can migrate to food items, especially as this tough, resilient plastic eventually breaks down after repeated use and/or heating in the microwave.

For now, the verdict, you could say, is as clear as glass: “Extensive safety data on BPA show that polycarbonate plastic can be used safely in consumer products,” the American Chemistry Council says. “... the use of polycarbonate plastic for food-contact applications continues to be recognized as safe by the U.S. Food and Drug Administration … and other regulatory authorities worldwide.”

The latter point is noteworthy because some of these authorities, such as the European Food Safety Authority, have more stringent standards than the United States FDA. And the EFSA says that its “comprehensive re-evaluation of bisphenol A (BPA) exposure and toxicity concludes that BPA poses no health risk to consumers of any age group (including unborn children, infants and adolescents) at current exposure levels.”

Caution flavors the debate

For its part, Tupperware pledges to remain vigilant about polycarbonate, saying it “will continue to closely monitor this scientific debate and research the best materials for use in its products.”

In the meantime, consumers ought to inspect plastic containers for their resin code and avoid category 7 plastics, the Academy of Nutrition and Dietetics says. “Go BPA free,” it says before advocating a better-safe-than-sorry strategy: “Glass is overall a safer bet for food storage than plastic.”

The defense council agrees that it's wise to err on the side of caution: “Glass, ceramic and stoneware are the safest options when it comes to food packaging and storage because they do not leach any questionable chemicals when in contact with food.”

While many culinary experts appear to be fully informed about polycarbonate, they tend to balance safety with practicality and function. They note that while plastic is lightweight and durable, glass meal prep containers can be heavy and breakable. But glass offers advantages, too. Namely:

  •  Their transparent quality makes it easy to identify and manage food storage
  • They transfer easily from the refrigerator to the microwave
  • They look attractive on a tabletop

And with that ushers in the issue of personal choice, much like the almonds-in-the-bag-or-in-a-bowl choice. Whether you choose glass, plastic or a combination of the two meal prep containers, you will find assurance in Meal Plan Magic, a fresh meal planning tool that can help you plan fresh meals and snacks, write a shopping list, choose fresh ingredients at the store and then maybe even surprise yourself with the results. If “fastidious” doesn't describe your nature now, it will as you learn to rely on the precision of Meal Plan Magic.