system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are vegetables and fruit so important for your diet?
gpt
Both veggies and fruits have a ton of vitamins that humans don't naturally produce. Several vitamins originate in plants, with the amount we get from eating meat being diminished by the animal in question using them.

Vegetables have tons of fiber, which is good for your digestive health because humans can't digest most fiber. This helps keep you more regular, as it increases the amount of solid excrete you make.

Leafy veggies are low calorie and high in vitamins, so you can eat a lot of them without it having a significantly effect on your weight, which is why people on weight loss regimens are told to eat more leafy greens.

Starchy veggies like potatoes have more calories while still being rich in vitamins, so they are a good alternative. However, once they've been processed they lose a lot of that health value, which is why potato chips and french fries aren't really great for you, especially commercially produced ones that are basically soaked in vegetable oil.

Vegetable oil, despite being made of vegetables, is pretty awful for you. Olive oil is almost always going to be better for you. 

For fruits, they are in a strange spot. Most berries are basically balls of sugar, but they do have plenty of vitamins as well, so you should eat them but primarily as snacks. It is not going to be healthy once you pass your first bowl of strawberries, and fruit cups are generally a generous but good amount of fruit to eat. Citrus fruits are famous for being good sources of vitamin C(a deficiency of which causes scurvy), but you can get vitamin C just as well from broccoli, kale, and brussel sprouts.

Anyways just eat veggies.