"Just as you can gain weight on a vegan diet if you eat French fries and Oreos, you can gain weight going gluten-free," she said.
Neily said people often overdo gluten-free snacks and baked goods because they have a "health halo" surrounding them.
"Gluten-free doesn't mean calorie or fat free. If these foods are a big part of your diet, you probably won't be losing weight," she said.
Her point is well taken: Gluten-free Glutino pretzel sticks, for example, contain 120 calories per ounce, compared with 100 calories per ounce for standard pretzel sticks. Gluten-free chocolate chip cookies are approximately 110 calories per cookie, while a regular chocolate cookie is about 90 calories. Gluten-free chocolate cake delivers approximately 280 calories and 5 grams per slice, slightly more than a piece of chocolate cake with the gluten intact.
Although the gluten-free weight-loss fad shows no signs of slowing down, some dieters are catching on – and giving up.
Dyana Flanigan a 48-year-old public relations manager from Chicago, said she tried a gluten-free diet for six months and wound up gaining 5 pounds.
"I really don't know why I gained weight. Maybe because I was eating more of other things as a reward for denying myself what I really wanted," she speculated.
And, she said, she found gluten-free an expensive way to eat. She was shocked to pay $8 for a bag of gluten-free pretzels when a similar bag of regular pretzels cost around $2.
Although she didn't lose any weight, her pocketbook definitely did, she said.
Now, we want to know what you think. Have you tried going on a gluten-free diet to lose weight? Did it help? Do you have celiac disease or know someone who is gluten sensitive who resents when others go gluten-free "just because"?
Leave your opinion in the comments section below and join our celiac and gluten sensitivity tweet chat today at 1 p.m. ET. The chat will be moderated by ABC News chief health and medical correspondent Dr. Richard Besser. Experts from topic celiac and gluten-free organizations, such as the Mayo Clinic, the American Gastroenterological Association and the Celiac Sprue Association will be tweeting their thoughts. Joining the tweet chat is easy. Click here for more details.