Are Food Sensitivities Making it Harder for You to Lose Weight?

Losing weight can feel like such an uphill battle. Whether you’re dealing with cravings, stress eating or hormonal imbalance, there are lots of potential roadblocks that could keep you from reaching your goal on the timeline you expected. But, is eating foods that don’t agree with you a potential contributing factor to slow weight loss? Here’s what experts had to say, plus how to deal if you suspect you have a food sensitivity.

“While food sensitivities, intolerances and allergies are often used interchangeably, they don’t mean the same thing and there are key differences between them,” says Pam Cureton, RD, who specializes in the treatment of celiac disease.

Food allergies are an immune system reaction. Specifically, when you’re allergic to a food, your immune system creates immunoglobulin E (IgE) antibodies in response to consuming it, according to the American Academy of Asthma and Immunology. Though the symptoms of food allergy vary, they can range from anaphylaxis (a total-body reaction that requires immediate medical attention) to itching, burning, hives or swelling of the skin. The symptoms can be widespread, but often involve the mouth, throat, tongue or lips, adds Anna Binder-McAsey, RD, owner of Rethink Nutrition.

Food intolerances, on the other hand, are usually GI-related. They happen when the body has a hard time digesting a certain food. “The most common example is a lactose intolerance, which happens when someone lacks enough of the digestive enzyme lactase to digest lactose, a sugar found in cow’s milk,” McAsey explains. These reactions happen almost exclusively in the GI tract, meaning they primarily cause digestive symptoms, and don’t cause the widespread immune response seen with allergies.

Food sensitivities are understudied compared to allergies and intolerances, Cureton says. They’re similar in the sense that they’re immune-mediated reactions to particular nutrients (meaning the immune system is involved), but they’re not exactly the same as food allergies, and they’re not as well-understood. “Importantly, the symptoms of the sensitivity can change, meaning that reactions don’t always happen the same way,” Cureton says. One day, eating the nutrient you’re sensitive to could result in a stomachache, the next day it could produce eczema, the next day it could result in joint pain, she explains. That can make food sensitivities tricky to pin down.

The most common substances involved in food sensitivities include FODMAPS (especially fructose), dairy, gluten, caffeine, amines, and sulfites, according to Amy Davis, RD. Generally, food sensitivities tend to contribute more to chronic inflammatory symptoms such as diarrhea, eczema, psoriasis, migraines, acid reflux or joint pain and swelling, McAsey says. “It would be common for someone with a sensitivity to experience symptoms on a very regular basis, such as daily or weekly headaches or persistent eczema.”

For starters, if a person is having a hard time losing weight but not experiencing any other symptoms, food sensitivities definitely aren’t the first thing to look into, McAsey says. And there’s no published scientific research that concludes food sensitivities cause weight gain, Cureton adds.

That said, if someone is having GI issues, eczema, psoriasis or any other inflammatory symptoms along with weight-loss resistance, then food sensitivities could be considered a potential factor, according to McAsey. That’s because there are a few different ways food sensitivities might contribute to having a hard time losing weight.

First, most research on weight and inflammation looks at how increases in weight lead to inflammation — not the other way around, McAsey says. But in her clients, she’s observed that once underlying inflammation from food sensitivities is addressed, weight loss becomes easier. “Once someone is in a healthier state, we typically see that they’ll settle into a healthy weight for their body without having to resort to intentional weight-loss strategies,” she notes.

Secondly, food sensitivities generally make people feel unwell. “When we don’t feel well, it’s difficult to spend energy on activities like exercise and cooking healthy meals, which are essential for weight loss,” Davis points out.

Food sensitivities can also cause bloating and discomfort that may mimic weight gain, Cureton says. Plus, if you start restricting the foods you eat because you’re not sure which foods are causing symptoms, you might end up eating more processed foods, which increase calorie intake and may exacerbate bloating, Cureton explains.

CONSIDER AN ELIMINATION DIET

Experts agree that for getting to the bottom of food sensitivities, an expert-guided elimination diet is your best bet. “A comprehensive elimination diet where certain foods are removed, then reintroduced individually can identify offending foods,” explains Tina Marinaccio, RD, CPT.

Elimination diets can be tricky to implement on your own, which is why experts recommend seeking help from a dietitian or another qualified provider if you want to go down this route.

SKIP FOOD SENSITIVITY TESTING

At the moment, there are no food sensitivity testing methods that are widely accepted. “Food sensitivity tests typically look for the presence of IgG, not IgE, which is used in allergy testing,” Cureton says. This type of testing can be expensive and hasn’t been shown to reliably identify sensitivities, which is why nutrition and allergy pros generally opt to go the elimination diet route instead.

GET HELP FROM AN EXPERT

“Before self-diagnosing and treating a suspected food sensitivity, the advice of a medical professional is essential,” Cureton says. Bloating, abdominal pain and weight gain can be caused by a number of medical issues, she points out, and your diet might not be the culprit.