That doesn't mean you shouldn't encourage kids to try new things, but they are not going to end up unhealthy if they sat at the dinner table for an hour and still didn't eat that cabbage. And it debunks claims that picky eaters are at higher risk of being underweight, with poor growth, or being overweight.
The study examined if people identified as picky eaters showed differences in height, weight and body composition from their non-picky peers. Height and weight were followed for 10 years and chosen from the Avon Longitudinal Study of Parents and Children cohort at 3 years of age.
Height and weight were measured on seven occasions in ages 7-17. Body composition was measured on five occasions by dual-energy x-ray absorptiometry (age 9-17 years). Participants were classified as thin/normal/overweight or obese at each age point using body mass index (BMI) classifications. Instead of being harmed by picky diets, BMI and lean mass were lower in the picky children. The mean heights, weights and BMIs of picky eaters were consistently above the 50th centiles of reference growth charts while more than two-thirds of picky eaters were not underweight at any age point.
In an increasingly obese world, looking for ways to make thin kids eat even more food is unnecessary. Expose kids to diverse diets and food choices, but don't force them to eat.