Both sentences are correct and they mean the same thing (mostly). Your first sentence sounds more natural and is more commonly used. By putting the word "the" in front of vegetables, it emphasizes that there are specific vegetables that the people have not eaten. The second sentence is a little more vague, and might fit better for when one is talking in generalities.

The first sentence is best. It sounds like you are reinforcing a certain type of vegetable.

Sometimes yes, sometimes no. If you are talking about vegetables as a concept, then no. For example: I like vegetables. Vegetables are healthy. A good source of vitamins are vegetables. If you are talking about vegetables in a more specific way, than yes. For example: Please put the vegetables on the table. The vegetables are almost done cooking. I looked for the vegetables in the refrigerator. Good luck! 祝你好运

Here is my takes: Both are correct. If you add 'The' before vegetables, it refers to some specific or particular vegetables.If without 'The', it refers to any kind of vegetables.

Hey Ootred ~ Yes, you need the "the." Try rephrasing for smoothness: "People often leave the most nutritious part of the vegetable." "Often the most nutritious part of the vegetable is left uneaten."