I despised eating breakfast when I was in elementary school. Not because I didn’t like food (I love food), but because I’d rather use those extra 20 minutes to sleep. This, of course, was a huge mistake—I’d get nauseous, fall asleep in class, and be overall cranky, distracted, and foggy-headed until lunchtime came around and I could fill my stomach with something substantial.

None of this has changed since I’ve gotten older. If I skip my first meal of the day, I might as well have given up my morning or been five drinks deep—my focus and productivity just isn’t at its peak.

And this isn’t mental either: Studies show that eating breakfast does a heck of a lot of good for you—and, on the contrary, not eating it has plenty of downsides.

Here’s the general scientific gist of why it’s important, according to a 2014 Harvard Business Review article:

Just about everything we eat is converted by our body into glucose, which provides the energy our brains need to stay alert. When we’re running low on glucose, we have a tough time staying focused and our attention drifts. This explains why it’s hard to concentrate on an empty stomach.

You probably already knew that from Intro to Biology 101, right?

But getting food into your system first thing in the morning has other benefits, too. Research shows it can help you lose weight, decrease the risk of developing diabetes, or heart disease.

And—here’s a fun fact for you—one study cited in the Independent suggests that eating ice cream for breakfast can make you smarter.

So why don’t you eat it? Maybe you think you’re too busy, or aren’t hungry that early in the day, or, like seven-year-old me, would rather sleep in than make yourself some food.

These excuses are fine, but if eating this one meal can be that powerful, why wouldn’t you do it? No really, forget all the other productivity hacks—because the best one is right in front of your nose.

Now, if you really want to eat stuff that’ll count, you can try incorporating these nutrients into your diet.

But the good news is you don’t really have to worry about the nutrients. All you have to do is spend five minutes cooking some eggs, or throwing a piece of bread in the toaster oven, or scooping a little ice cream into a bowl while you get ready for work.

It’s really that simple.