Lisa Yates has a 13-year-old who cannot eat nuts and an 18-year-old who will not eat gluten. When the family hops on a train on Thursday to visit relatives for Thanksgiving, Ms. Yates will be carrying nut-free chocolate, gluten-free banana bread and two containers of stuffing – a nut-free version and a gluten-free version.

“It’s challenging, but you get used to it,” said Ms. Yates, a community development consultant from New York City who has instructed her sister, who is hosting the holiday in Virginia, to send her pictures of the ingredient labels of all the foods she’s using.

Ms. Yates has plenty of company. One in six parents has a teenager who has tried either a vegetarian, gluten-free, vegan or paleo diet within the last two years, according to a new survey of 910 parents of teenagers from the University of Michigan C.S. Mott Children’s Hospital. The parents were a nationally representative sample, and all had at least one child between 13 and 18.

Many of the parents said they believed the diets were good for their child’s health, but that they found the restrictions challenging and often stressful, said Sarah Clark, co-director of the poll and lead author of the report on it.

Special diets can be a source of tension during the holidays, the survey found, and over half of parents whose teenagers follow special diets said the diets caused conflict at family gatherings.

“So much is built up around these special holiday meals where we all are supposed to come together in harmony,” Ms. Clark said. ”But there are a lot of food traditions that run smack-dab into conflict with the diet.”

Arguments with extended family members can carry over to the parent-child relationship, she said. “Two things go on: The teenagers don’t like to be belittled for something that, for them, is a serious choice, and the parents feel judged based on what their kids do,” Ms. Clark said.

Developing a strategy in advance may help teenagers feel their choices are respected, and minimize disruption.

Some families respect that a child cannot eat certain foods because of an allergy, like that of Ms. Yates’s son, but roll their eyes at diets they consider optional, like being vegetarian.

Teenagers who adopt a special diet are often exploring their identity and declaring their independence, Ms. Clark said, and parents can take advantage of family get-togethers to demonstrate their support for their child’s choices.

But keep in mind that rejecting someone’s signature dish may appear insensitive or downright rude.

“It’s not unusual to hear about an older relative bursting into tears because a teenager wouldn’t eat the dish that was their special contribution and that everybody always raved about,” Ms. Clark said. “It’s seen as impoliteness, and a slap in the face.”

Tensions may be eased if family members are informed of the child’s dietary preference in advance or if a child is willing to compromise and taste a small portion, she said.

The poll found that the vegetarian diet was the most popular: 9 percent of teenagers — nearly one in 10 — had tried it. Six percent had tried a gluten-free diet, 4 percent a vegan diet and 2 percent a paleo diet.

Among those parents whose children followed restricted diets, over half said they thought the diets had a positive impact on their child’s health, while 41 percent believed it had no health impact, and 7 percent thought it was bad for the child’s health.

But while 11 percent of parents forbade their child to embark on a special diet, only 17 percent had asked a nutrition expert for advice. Dietitians urge parents — and teenagers — to consult a professional before embarking on a new diet, not only to make sure the child will get all the nutrients needed, but also to discuss the child’s motivations and help screen anyone with an underlying eating disorder whose real motivation is losing weight.

“Teenagers want to start calling their own shots and taking responsibility for their decisions, and that’s a good thing, but we need to find out why they’re doing it,” said Angela Lemond, a registered dietitian nutritionist in Plano, Tex., who is a spokeswoman for the Academy of Nutrition and Dietetics. “Sometimes, when you unpeel the onion, it’s just another way of trying to eat less.”

Each diet presents its own set of potential nutritional pitfalls, Ms. Lemond said. Vegans need to make sure they get enough protein as well as vitamin B12, iron, calcium and vitamin D, while those following a paleo diet who don’t consume dairy products have a hard time getting calcium, vitamin D and fiber. And everyone needs to get sufficient calories; if teenagers don’t consume enough, she warned, “it will stunt their growth.”

The survey found that teenagers’ reasons for starting restrictive diets varied.

About one-third of the children changed their diets for health related reasons, and just under one-third said they did it because another family member practiced the diet. One in five were following a friend’s suggestion, and one in seven said they were motivated by concern for the environment.

Parents whose children followed special diets cited several challenges. Some 61 percent said it was difficult to find places to eat out as a family, 55 percent said it was hard to find the time to prepare special foods, 54 percent said it was stressful, half said it was costly and 51 percent said it caused conflict at holidays and family gatherings.

In the interest of family harmony at the Thanksgiving table, it could help to take a page from Ms. Yates: Go bearing Tupperware. And if your child is determined to pass on the turkey or sweet potato soufflé, just smile and pass the next dish around.