Been feeling bloated… and sluggish… with a foggy brain and middle school-level breakouts? Let’s say you’ve been getting enough sleep and exercise and you know your mental health is in check. So what in deep hell is going on with your body?

That’s when a sponsored Instagram naturopath might suggest it’s food-related. Facebook then says, “Hey, why not try a food sensitivity test?” And you think, “Sounds solid…right?”

But before you order that test kit in the hope of finding a quick answer, there’s something you should know about the fine print. These kits remain controversial within the medical and nutrition communities, and their terms are often poorly defined.

Here’s what to know before you take the plunge (and drop the cash) for food sensitivity testing.

The guidelines around what “counts” as a food allergy are well-established, and true allergic reactions can be documented via tests of your blood or skin. A genuine food allergy happens when your immune system treats a specific food as an invader.

So when someone who’s allergic to tree nuts accidentally gets almond milk in their coffee, they’re likely to break out in hives, vomit, itch, or even go into anaphylactic shock. The results can get gnarly, making this definition pretty clear-cut.

And food intolerances? We know a lot about lactose intolerance (which is the inability to digest the lactose in dairy foods) and the discomfort it can bring. An intolerance might not be as dangerous as an allergy, but it can still cause distress.

But the intolerances or sensitivities that happen with less common culprits like pineapple or avocados are harder to explain. “There is still so much we don’t understand about how the body reacts to foods and our environment,” says Julie Stefanski, RDN, a spokesperson for the Academy of Nutrition and Dietetics (AND).

“Unlike food allergies, intolerances do not involve the immune system and are not life-threatening,” says Sonya Angelone, MS, RDN, CLT, also a spokesperson for the AND.

It doesn’t help that food sensitivities are much less well-defined — and there’s little consensus on what separates a sensitivity from an intolerance. Often the two terms are used interchangeably. The AND offers no official definition of either term on its website.

According to Angelone, “Food sensitivities are delayed reactions that can affect any organ system of the body and can take from 45 minutes to several days to manifest in symptoms.” We’ve gotta admit that’s a pretty broad interpretation that also describes food intolerances.

In light of all the confusion, many health professionals are suspicious of the concept of food sensitivity.

“Food sensitivities are a nebulous term applied to various symptoms people may experience after eating specific foods,” says Dr. David Stukus of Nationwide Children’s Hospital and The Ohio State University College of Medicine. In some ways, “food sensitivity” has become a catch-all term to address common symptoms that have yet to be explained by science.

You may notice slight discomfort when you eat a certain food, and you may learn to avoid that food, but how can you really be 100 percent sure? If the definition of food sensitivity is so vague, what are companies testing for?

A food allergy test can be done via blood draw or skin prick to see if a particular food causes your antibodies to overreact. Food sensitivity tests, though, use other methods — and which test a company uses is really important in keeping calm.

One option, the “cell-based” ALCAT test, looks at how your white blood cells respond when “incubated with purified food and mould extract.” The Mediator Release Test takes this concept one step further, monitoring whether your cells release inflammatory markers when exposed to various foods.

One particularly hot-button sensitivity test is the IgG (immunoglobulin G) test. Many people have criticized this test for simply revealing which foods a person has recently eaten, not the ones actually causing symptoms.

“IgG goes up in response to eating a food and does not correlate with symptoms and is not a good marker for an inflammation reaction to food,” says Angelone. As of 2018, more than 25 health organizations have cautioned the public about the misinterpretation of this test.

Getting tested for food sensitivities may seem enlightening at best. It might seem harmless, too, but there’s more to it when diet culture comes into play. In a culture focused on putting foods into “good” and “bad” categories and treating food as medicine, the results of a test could trigger or encourage disordered eating.

“A disordered relationship with food can affect the gut and in essence mimic the symptoms of food sensitivity due to stress and anxiety about eating,” says private practice dietitian Annie Goldsmith, RD, LDN. “Clients often find themselves in a vicious cycle of blaming specific foods for these symptoms and doubling down on their restriction, thereby making symptoms even worse.”

The thing about funky, inconsistent symptoms is that you might not need to go to the trouble (and expense) of food sensitivity testing to get to the bottom of them. Many issues with food can be resolved by less invasive means.

“Added ingredients such as artificial fibers, sweeteners, or other culprits can often be identified with a thorough diet analysis and client interview,” says Stefanski.

“Whether a food has to be completely avoided really depends on the type of reaction a person has,” says Stefanski. Because the definitions of intolerance and sensitivity are so vague, you’re better off working with professionals to get to the bottom of your symptoms.

“Working with a team of an allergist, registered dietitian, and gastroenterologist helps someone to determine whether they have a serious condition in which foods will need to be avoided for an extended time,” adds Stefanski.

And there may be hope for improvement over time — for the accuracy of these tests and for you.

“Often, sensitivities can improve once inflammation is decreased and other problematic foods are removed,” says Angelone. “However, sometimes a person will always be sensitive to a particular food.”

Ordering a test kit from an Instagram ad might sound reassuring, but when it comes to knowing what your gut is sensitive to, going old school might be the key. Trying an elimination diet and keeping a food diary that lists what you ate and how you felt over a 24- to 48-hour period might be more effective in identifying troublesome foods.

An elimination diet may feel like annoying advice, but when it comes to long-term comfort, especially as you get older, it can be incredibly helpful for figuring out food sensitivities and intolerances. The diet involves simplifying your meals (for example, chicken, spinach, rice) and slowly reintroducing different foods each week to see if anything causes a bad reaction.

Still feel like a food sensitivity test kit is the right choice for you? Talk to a registered dietitian, allergist, or GI doctor to figure out your best game plan.

Sarah Garone is a nutritionist, freelance writer, and food blogger. Find her sharing down-to-earth nutrition info at A Love Letter to Food or follow her on Twitter.