An unbalanced diet or picky eating habit—favoring certain foods to the exclusion of others, often leading to nutritional imbalance.
子どもの偏食で野菜を全然食べないので心配だ。
I'm worried because my child is picky and hardly eats any vegetables.
偏食が続くと、栄養不足や健康障害の原因になる。
Continued unbalanced eating can cause nutritional deficiencies and health problems.
医者から偏食を直すように指導を受けた。
The doctor advised me to correct my picky eating habits.