(名詞) 入門蔬菜 － 一種美味可口的蔬菜，長期食用會激勵食用者更大膽地吃其他蔬菜。cf. gateway drug (入門毒品)。
Healthy eating and weight loss requires vegetables. There's no way around it. Some of us would rather fill our plates with meat and bread. If you discover a "gateway vegetable" you'll start eating them more often.
—Dave Greenbaum, "Discover Your 'Gateway Vegetable' To Start Eating Healthier," Lifehacker Australia, October 12, 2014
We call pea shoots the "gateway vegetable," because when we grow them in the classroom, children just eat them by the fistful until green juice is running down their faces.
—Emily Armstrong, "Harvest of the Month: Pea shoots," Martha's Vineyard Times, February 23, 2015