Kelly Hall, a 35-year-old working mother of three children — ages three, eight and 15 — admits that her family eats fast food three times a week.

Compared to her husband who gives into their children’s whining a little more often, she is a strict parent who understands that junk food causes dental and other health problems. But her full-time job as a personal shopper in Washington, D.C., and her husband’s job play a big role in making their children’s diet “not very healthy,” she says.

“It’s not easy to take the kids to a grocery store and pick the right things. They always want the sugary things,” Hall said.

Ninety-seven percent of parents in the U.S. think that childhood eating habits determine children’s health for their lifetime, but only 17% say their child’s diet is very healthy, according to a recent national poll by the C.S. Mott Children’s Hospital.

The national survey, published on Feb. 20, was taken in October 2016 among 1,767 parents with at least one child age four to 18.

According to the survey:

-- 73% rate their children’s diet as very or mostly healthy.
-- 27% rate their children’s diet as somewhat or not healthy.
-- 34% are confident they are shaping good eating habits of their children.
-- 21% say it is somewhat or not important to cut down on junk food or fast food.
-- 16% believe it is somewhat or not important to reduce sugary drinks.
-- 13% say it is somewhat or not important that their child eats fruits and vegetables every day.

Sarah Clark, the survey’s co-director and associate research scientist at the University of Michigan, said there should be more understanding that it’s not easy for many parents to provide a regular, healthy diet for their children. She suggested parents take away this message: “You are not alone. For most of us, this feels like an unending battle.”

Clark said she was stumped by the result that one in five parents do not think it's important to limit unhealthy food, even though most of them know they should. But she realized after analyzing the data that such an attitude is prevalent among parents of teenagers.

“When my boys were teens, their appetites were boundless – and at a certain point, it almost didn’t matter what they were eating," she said. "So my guess is that other parents may be having the same feelings."

The survey results are positive in the sense that most parents recognize that healthy eating is the goal, Clark said. But there’s a problem if one in four parents in the country acknowledge that their kids’ diet is not the ideal, she said.

Parents face several day-to-day challenges, but the main problem (70%) behind an unhealthy diet is the high cost of healthy food. The next reason (60%) is children's preference for sugary and fatty food. Parents with a low-income level and low education have a hard time determining which foods are healthy (52%), or those food are unavailable where they shop (23%).

Research shows that frequent consumption of fast food leads to heart disease, obesity, headaches, acne, high blood pressure, dental problems and high cholesterol. Diet also affects mental health. People with a low-quality diet — processed meat, chocolates, sweet desserts, fried food, refined cereals and high-fat dairy products — are more likely to suffer from depression, according to Katherine Zeratsky, a certified dietitian in the American Dietetic Association.