What You're Really Eating When You Buy Pre-Made Meals From Grocery Stores

It pays to know the best grocery stores to pick up a pre-made meal. This modern convenience is to the 2020s what sliced bread was to the 1920s: A welcome innovation that could be leveraged easily while making a single stop at the grocery store. Unlike salad bar and buffet foods, which are also available at many supermarkets today, pre-made grocery store meals come cleanly packaged in neat little containers. And in most cases, the instructions encourage us to heat them up in those neat little containers — without dirtying another dish.

But just as sliced bread has managed to acquire its share of critics over the years, so too have pre-made meals. To wit, a 2015 study published in the academic journal, Appetite, begins with quite the damning statement about these foods that were designed to make our lives easier. "Over-reliance on convenience foods, including ready-meals, has been suggested as one contributor to obesity," the authors assert. On the other hand, the authors immediately follow up with the observation that clinical research on the nutritional content and health consequences of consuming "supermarket ready-meals" had been sparse up to that date. 

Fortunately, while research on the topic remains in short supply to this day, a lot more is known today than was in 2015. And while it turns out that what you're really eating when you buy pre-made foods from the grocery store isn't quite what we had hoped, it's not all bad either.

Federal law requires most packaged foods you can buy in grocery stores be labeled with a "major food allergen" disclosure — i.e., a statement as to the presence of one or more of the nine major food allergens: Milk, egg, fish, shellfish, tree nuts, peanuts, wheat, soybeans, and sesame. Most pre-made grocery store food is labeled appropriately in that respect. However, mistakes do happen. For example, this Trader Joe's recall of one of its most popular ready-made salads came about because it contained undisclosed wheat, one of the major food allergens. 

Of course, some people have allergies to foods that are not included on the list of "majors." In fact, more than 170 different foods are associated with allergic reactions in humans, according to Food Allergy Research and Education (FARE).  Although most involve the nine majors listed above, some 10% of the 32 million people in the U.S. with food allergies are sensitive to foods that are not. Although no disclosure statement needs to be made about these other potential allergens, they should appear on the ingredient label. Unfortunately, federal law doesn't always require an ingredients list on pre-made food, and some states don't either. 

The downside is some pre-made foods are packaged without an ingredients list. Even worse, some of the ingredient lists you see may be less than reliable. For example, Consumer Reports noted that a Stop & Shop spicy tuna roll contained avocado but did not disclose "avocado" in the ingredients list.

Pre-made meals from the grocery store may also harbor contaminants — i.e., things that aren't supposed to be there at all. One such type of contaminant is bacteria — the kind that causes foodborne illness, such as any of the potentially life-threatening illnesses caused by Salmonella, E coli, or Listeria bacteria. Pre-made meals present a heightened risk of what's known as cross-contamination because meals tend to involve a variety of foods, not all of which are cooked at temperatures high enough to kill foodborne bacteria (165 degrees Fahrenheit). 

For example, if a dish is made with chicken and carrots, and the cook uses the same knife to cut both, the carrots can be contaminated with whatever bacteria is on the chicken. Most likely, the chicken will be cooked to the critical temperature whereas the carrots may not be. Recalls of pre-made foods due to actual or suspected bacterial contamination are a lot more common than any of us would care to think. For example, in February 2023, a vendor of ready-made sandwiches and wraps issued a recall due to potential cross-contamination with Listeria (via the FDA). In April 2023, Meijer recalled pre-made salads due to potential Listeria contamination.

Cross-contamination can also introduce trace amounts of undeclared allergens into pre-made food. In 2020, the FDA issued a warning to Whole Foods for numerous instances of the same in its pre-made foods.

In addition to salt, pre-made supermarket meals tend to be high also in saturated fat, according to findings in the 2015 study published in the journal, Appetite. Sources of saturated fat, which you'll recognize by its solid state at room temperature, include butter, cheese, red meat, poultry, lamb, and pork — all of which are used quite often as ingredients in pre-made meals from the grocery store and elsewhere. 

Saturated fat is one of the types of fats that scientists, including cardiologists, would rather you strictly limit (the other is trans fat). Habitual consumption of more than the recommended allowance can cause blood levels of LDL cholesterol (i.e., the bad one) to rise, which can, in turn, increase your risk of heart disease and stroke. The American Heart Association recommends that adults limit their daily consumption of saturated fat to the equivalent of 5% to 6% of their total calories. In other words, for every 1,000 calories consumed, no more than 60 should come from saturated fat. That's the caloric equivalent of around half a tablespoon of butter.

For an adult consuming 2,000 calories per day, that translates to about 12 to 13 grams of saturated fat per day. And those grams add up perhaps more quickly than you'd like when the average pre-made meal analyzed by the researchers in the 2015 study was 7.2 grams per serving, with the full range being 3.5 at the low end and 11.8 at the high. And remember, per serving doesn't usually translate to what most of us would consider a single portion, so we're likely consuming even more.

If the salt and saturated fat content in the average pre-made grocery store meals have you feeling concerned, let's not forget that in addition to the many options available for home-delivery of healthy pre-made meals, your local supermarket may stock some pre-made meal options that are labeled as "healthy" or "healthier" as well. The caveat, however, is that you still should read the label to determine whether any given meal's idea of "healthy" or "healthier" is in line with your personal definition. 

For context, the FDA allows a "healthy" label only on pre-made meals that have less than five grams of fat and two grams of saturated fat per 100 grams (which, for most meals, will be less than an actual serving), less than 600 mg of salt and less than 95 mg of cholesterol. As noted above, many pre-made grocery store meals analyzed by the researchers for the 2015 study contained well over those amounts, including a number that were labeled as "healthier." 

The takeaway here is that you should trust but verify "healthy" claims on pre-made grocery store meals. And one of the things you should verify is whether the actual numbers on the label are consistent with your own dietary needs and goals.

Pre-made meals don't just save you time on prepping and cooking. They also offer the convenience of going from refrigerator to microwave to table without dirtying so much as a single plate. But if your pre-made meal comes in a plastic container, you may want to consider, before indulging in said convenience, that microwaving food in plastic containers may cause chemicals from the plastic to leach into the food, according to the World Health Organization (via Sharp). And to answer the question that's probably on your mind, that's true even if the plastic container is "microwave safe." Indeed, a "microwave safe" designation means only that the plastic won't melt while it's cooking your food. That doesn't mean it won't leach.

The question becomes whether your health can be harmed by consuming foods into which plastic chemicals have leached. As Laura Vandenberg, a professor of environmental health science at UMass-Amherst, told Men's Health, the chemicals that have raised the most concerns are bisphenol A (BPA) and phthalates, both of which are sometimes found in food that's been cooked or heated in plastic. And the FDA takes the position that the low levels found in foods cooked in plastic do not raise significant health concerns.

But you may or may not feel comfy relying on that when it's your and your family's health at stake. That's why Vandenberg recommends taking that extra step of removing your ready-made meal from its plastic packaging before heating it in the microwave.