After suffering from gastrointestinal issues and nonstop fatigue for months, I visited a naturopath for some guidance. She put me on a very specific gluten-free diet, thinking gluten, a protein found in wheat, barley and rye, might be the source of my problems.

Sticking to the diet was easier said than done. Gluten can be found in a surprising number of foods—such as some soy sauces and salad dressings—and I was overwhelmed by all the restrictions. For a few months, I loaded up on items from the health food store that were labelled "gluten-free": pasta and muffins made with rice flour, cashew-butter cookies and corn tortilla chips.

While I felt no better and ultimately ditched the diet—the only thing I gained was a few pounds—the lack of variety in the foods I was eating meant I was also potentially putting myself at risk for nutritional deficiencies.

More and more people are changing their diets as a result of a self-diagnosed food intolerance. Despite my personal experience, some people say that cutting out gluten, dairy, eggs or wheat has made a difference in their overall health and happiness. But what's really going on? Will switching up your diet actually help your health?

What is a food intolerance?
A food intolerance is an adverse reaction to a food that doesn't involve an immune response, making it different from a food allergy. Symptoms vary but typically include gastrointestinal issues, such as abdominal pain, gas, bloating and diarrhea, and non-GI symptoms such as headaches and joint pain.

Food intolerances may occur when you don't have enough of an enzyme to fully
digest a particular food. People who are lactose-intolerant don't have enough lactase, for example. Those with intolerances may also experience delayed symptoms. "You can consume something today and only experience symptoms tomorrow," says Afsoun Khalili, Toronto naturopath and associate professor at the Canadian College of Naturopathic Medicine.

How is an intolerance diagnosed?
If you suspect you have a food-related reaction, consult a medical professional before making any dietary changes. If you're referred to an allergist, he or she will ask you for a comprehensive account of your history with the foods you suspect. "Truly, in many situations, the diagnosis can be made on the history alone," says Dr. Elana Lavine, Toronto pediatric allergist and clinical immunologist and author of a primer on food-sensitivity testing published in 2012 in the Canadian Medical Association Journal. To corroborate the history, an allergist will use other methods, such as a blood test or a skin-prick test, whereby a tiny bit of the contentious food, or extracts of the food protein, are applied to the skin to see if an immune response is generated.

Some health practitioners will recommend commercial food IgG antibody tests as assessment tools. These tests can cost upward of $400 and claim to identify food intolerances or sensitivities through blood tests, but Dr. Lavine has not found them helpful. "There's a lack of evidence when it comes to accuracy," agrees Kate Comeau, Halifax registered dietitian and spokesperson for Dietitians of Canada. "They typically just show us the foods you're eating most frequently."

While Dr. Lavine doesn't recommend commercial food antibody tests, she acknowledges that people undergo them with the best of intentions. "They're trying to advocate for their own health or for the health of their child but are left quite baffled about how to interpret the results." She has seen parents restrict the whole family's diet, removing staple foods such as milk, eggs and wheat and buying alternative products that may be less nutritious
and more expensive.

Are food alternatives healthy?
Comeau worries that avoiding a large number of foods could potentially put people at unnecessary risk of nutrient deficiency. "Some of the food alternatives on the market aren't a more healthful choice. In some cases, they're not healthful at all," she says.

"Research has shown that some gluten-free foods, especially staples like bread and pasta, have higher fat content and lower protein content than regular foods," notes Dr. Mohsin Rashid, pediatric gastroenterologist and professor of pediatrics and medicine at Dalhousie University in Halifax as well as professional advisory board member of the Canadian Celiac Association. He also notes that some people with celiac disease gain excessive weight when put on a gluten-free diet.

I recall the packaged foods I relied on during my own attempt at a gluten-free
diet. Some of them, like bread made with rice flour, were higher in calories than my regular bread (which might explain the weight gain).

While it's OK, after an intolerance diagnosis, to try a few processed products to help you avoid foods that are problematic for you in the short term, Comeau recommends gradually moving toward eating minimally processed foods and cooking meals yourself. The goal is to eat a variety of foods to ensure that you're meeting all of your nutritional needs.
Moderation is everything
If allergies or diseases have been ruled out and a food intolerance is identified, your physician or dietitian can advise you on making healthy diet changes. You may be able to consume small amounts of the food or drink without any problems. And if you do indulge, it may cause symptoms but not damage to the body. "I tell my clients it's their decision, and they know the consequences," says Comeau. "If a client is lactose-intolerant and really wants to eat ice cream, I say go for it! People need to own what they choose to do."

Check out what the differences are between food allergies, food sensitivities and food intolerances.

This content is vetted by medical experts

This story was originally titled "Can't Stomach It" in the March 2015 issue.             Subscribe to Canadian Living today and never miss an issue!