As part of our weeklong series, “What Experts Wish You Knew." we're talking about things we wish we had known long ago. And we chat with experts in different fields about things they wish their clients knew long ago.

In Part 3 of the series, we talked with dietitian Megan Landrum, from Eat with Zest, about the top five mistakes her clients make when it comes to healthy eating.

1. Failing to meal prep

Landrum says the most common problem she sees with her clients is that they don’t schedule or prepare meals ahead of time. She recommends marking down in your calendar about 2-3 hours a week for grocery shopping and batch cooking.

Make a big batch of grains like quinoa or rice -- or cook a rotisserie chicken. Then use those proteins in different dishes throughout the week.

2. Skipping breakfast

The second-most common mistake is skipping breakfast. After 6- 8 hours of sleeping, your muscles are deprived of glucose. If you don't eat first thing in the morning, your body breaks down lean muscle for fuel. This is basically your body going into starvation mode.

To avoid this, try to eat within an hour of waking up.

“I like to say: Eat like a queen for breakfast, split lunch with a friend and share dinner among many,” Landrum told us. “It gets you in this mindset of really nourishing for your day and not hitting that 3pm slump where you're overeating at the end of the day.”

3. Not eating before & after workouts

Mistake number three is failing to eat before and after your workout. You need to have some sort of carbohydrate within 30 minutes of your workout, and adding a little protein is even better. This is essential for building lean muscle and keeping your metabolism burning.

Landrum says to aim for 15-20 grams of protein after you exercise.

4. Focusing on quantity over quality

Mistake number four: Focusing too much on calorie counting.

An example: An apple and a cookie can each have 100 calories, but how each fuels your body is completely different. So instead of counting calories, focus on the nutrients in the food.

5. Letting "perfect" get in the way of good

Landrum's last tip: Don't let perfect get in the way of "good."

Healthy eating doesn't mean "perfect eating”; it's not all or nothing. If you eat unhealthy today -- you can always start fresh tomorrow.

Eating every 3-4 hours can help keep your hunger under control and guide you to making the best choices.

Check out our Facebook Live chat with Megan right here!

And check out other “What Experts Wish You Knew” topics we've covered: