"No dessert until you finish your vegetables!"

Whether you remember that phrase from your childhood or you said it to your kids just last night, we're all familiar with this classic parenting mantra. And, fair enough — it's a good one!

Vegetables are an important part of a healthy diet because they're packed with key nutrients, vitamins and minerals.

In particular, eating veggies is a great way to make sure you're getting plenty of fiber, which is beneficial for your health because it's associated with lower risk of:

• Heart disease
• Stroke
• Diabetes
• Certain types of cancer
  
  

In addition, vegetables are a high water content food — meaning they contribute to your daily water intake and aid in hydration (which comes with its own slew of health benefits).

However, making sure you're reaping all of the benefits that veggies have to offer might be bit more complicated than just understanding why they're healthy.

Here are five common veggie mistakes you may be making, as well as some advice for avoiding these mistakes.

You're not eating enough veggies to begin with

Did you know that only 9% of Americans eat enough vegetables every day?

It's recommended that you eat between 4 to 5 servings of vegetables every day, with a serving being:

• 1/2 cup of cooked vegetables
• 1 cup of uncooked vegetables
• 2 cups of leafy greens
  
  

This means that if you're having carrots and hummus, you'll need to make sure you eat a whole cup of carrots. If you're preparing sautéed spinach, reaching a serving of veggies takes 1/2 cup of the cooked spinach. And if you're having a salad, you'll need to bump the uncooked veggie rule up to 2 cups of leafy greens in order to reach a complete serving.

If you're struggling to get more veggies into your diet, start simple and save time by using frozen or canned vegetables. (Related: Are Canned & Frozen Veggies As Healthy As Fresh Ones?)

Your cooking method or co-ingredients are undoing the healthfulness of your veggies

Most veggies are low in fat and calories, and none contain cholesterol — all of which add to the health and weight-management benefits of vegetables.

However, your cooking method, as well as the co-ingredients of your veggie dishes, can easily undo some of the healthfulness of veggies.

When it comes to preparing veggies, avoid:

• Deep frying your veggies. Frying oils add excessive amounts of saturated fat to your dish. As a healthier alternative, try air frying the veggies you usually deep fry.
  
  
• Boiling the health benefits away. This cooking method leaches key nutrients, vitamins and minerals out of the vegetables and adds them to the water you discard after cooking. Try steaming your veggies instead.
  
  
• Adding unnecessary amounts of butter, cheese or heavy cream. These co-ingredients add both unhealthier saturated fats as well as cholesterol. Instead, pack in the flavor by turning to herbs and spices, or healthier fats, such as olive oil. You can also flavor veggies by cooking them with fresh garlic, which may also help boost your immune system and lower your blood pressure.
  
  

You're choosing veggies that are mostly starch

Now it's time for the bad news: Not all vegetables are created equal.

And when it comes to the veggies that are most likely to make you gain weight, look no further than our starchy favorites — white potatoes, corn and peas.

The main problem with starchy veggies is that they're not as high in fiber, so you lose out on one of the major benefits of eating vegetables. The other issue is that starchy veggies are more calorie-dense than their non-starchy counterparts.

This isn't to say that starchy veggies are bad, however. It just comes down to making healthier choices most of the time, and eating non-starchy veggies in moderation.

For instance, corn has more nutrients and would be a healthier choice than white rice, but broccoli is an even healthier choice than both corn and rice. With starchy veggies, it's really about portion size, since they don't come with the full health benefits of other veggies and can lead to weight gain if eaten in excess.

You're not eating the rainbow

When we think of veggies, most of us think of greens. Lettuce, spinach, kale, broccoli, Brussels sprouts, asparagus. Don't worry! Green vegetables are healthy. In fact, the darker the greens the more nutrients they typically pack in.

But there's a range of colors to consider with veggies beyond just green, which is why dietitians often recommend "eating the rainbow."

The color of a vegetable typically denotes the major nutrient within it. For instance, veggies that are red are high in vitamin A. Varying your veggies is important because it expands the range of nutrients you're getting from them — and eating the rainbow can help with this.

If you're stuck on how to add color to your veggie regimen, consider the following non-green veggies:

• Red, yellow and orange bell pepper
• Tomatoes
• Carrots
• Red onion
• Mushrooms
• Sweet potatoes
• Celery
• Eggplant
• Turnips
• Beets
• Yellow squash
• Red cabbage
  
  

And since eating the rainbow opens up the variety of veggies you eat, it can also be a great way to make sure you don't get bored of eating the same veggies — week in and week out.

You're not buying veggies that are in season

Speaking of being bored with veggies...

There's nothing like tiny, thin asparagus that shrivel immediately in the oven or carrots that just don't seem to have any flavor to make you question whether taking the time to prepare fresh, whole veggies is actually worth it.

When you choose veggies that are in season, they're often higher quality and more likely to be true-to-size, which improves flavor and might even benefit cooking outcomes. As an added bonus, seasonal veggies are often cheaper than out-of-season ones.

Use this guide from the USDA to find out which veggies are in season.