Here are some of the best breakfasts to keep you going all day

We've all heard that breakfast is the most important meal of the day, but just how important is it for your productivity?

By the time you wake up you likely haven't eaten for 10 or 12 hours, which is where breakfast got its name - it means "breaking the fast," Lisa De Fazio, a healthy lifestyle expert and registered dietitian, tells Business Insider.

Your first meal of the day is what kickstarts your metabolism and replenishes blood sugar levels so you can focus and be productive throughout the day. When blood sugar levels are low, she explains, it's much harder to focus and you're more likely to feel tired, irritable, and impatient.

Starting your day off on the right foot is all about balancing high-fiber carbohydrates with lean protein, De Fazio says. While all carbohydrates raise your blood sugar levels, high fiber carbs like fruits and whole-grain products do so at a steadier pace than sugar and low-fiber carbs like processed grain.

While you may be tempted to grab something quick and sweet like a doughnut or double chocolate muffin, De Fazio says these baked treats tend to be full of processed flour and sugar, which will spike your blood sugar levels and lead you to crash by mid-morning. "It's like injecting sugar straight into your bloodstream," she says.

Luckily, whether you make your breakfast at home, buy it, or keep something in the office kitchen, there are plenty of healthy and tasty options that will keep you from passing out at your desk.