Sally Marchini had only one symptom to suggest she could have coeliac disease.
"My iron levels were a bit low and, because of that, my doctor checked me for it," Ms Marchini said.
"It came back positive."
That was about 20 years ago.
"I hadn't heard of coeliac disease at that stage. It was well before I was a dietitian," she said.
"So for people wondering if they have coeliac disease, it's not always symptom driven."
Nonetheless, Ms Marchini said there were "more than 200 symptoms related to the disease".
"It's a condition of inflammation that affects the body all over," she said, adding those with the disease don't absorb nutrients well.
Once she was diagnosed, she "immediately went on a strict gluten-free diet".
"That's when I decided to go to university and study to be a dietitian for my own health and to help others," she said.
Coeliac Australia says about one in 70 Australians have the disease, but only 20 per cent are diagnosed.
It lists symptoms as including persistent gastrointestinal problems, prolonged fatigue, weakness and lethargy, mouth ulcers and unexplained weight loss.
Long-term health problems such as osteoporosis, liver disease, infertility and other autoimmune conditions can occur if the disease is not diagnosed.
Unexplained infertility or recurrent miscarriage are also linked to coeliac disease.
Ms Marchini will give a presentation on nutrition and fertility on Sunday at the Coeliac Australia Gluten-Free Expo in Randwick.
She said research showed "women with undiagnosed coeliac disease have an 8.9-fold increased risk of multiple spontaneous miscarriages".
About 16 per cent of Australian couples have problems with fertility, according to Family Planning Australia.
"There are also studies that show up to 67 per cent of these issues can be resolved with diet and lifestyle," Ms Marchini said.
"Many people think the issues all come from the woman, but the male side is just as important."
As for the gluten-free diet trend, Ms Marchini said it "was driven by books like Wheat Belly".
"You get celebrities saying 'I went gluten-free and lost all this weight'. It's not evidence-based," she said.
She urged people to get checked for coeliac disease before going gluten-free.
"Some people do have a gluten intolerance. If you find out that's the case, you may need to avoid it. But the gluten-free diet is not healthier."
She said gluten-free bread was mainly made from tapioca starch.
"It's just like sugar," she said.
She said this bread was "a poor nutritional swap from regular bread", as it was "higher in fat, lower in protein and low in fibre".
She was also concerned about people who follow meat-based keto or carnivore diets.
"They're not getting the nutrition their body needs. There are lots of examples of research that show it's unhealthy," she said.
"They end up with high cholesterol, a poor gut microbiome and their immunity gets shot."
