I know this advice is practically as old as time itself, but breakfast truly is the most important meal of the day. Since you've been sleeping for (hopefully) seven to nine hours, the idea is that you've literally got to “break your fast” and refuel to get your day going. And when it comes to those early birds with the stamina to wake up for a morning run, it's especially important to eat breakfast before exercise.
In fact, the ideal time to fuel up is about one hour before you start exercising, according to the Mayo Clinic. This gives you the right amount of time to digest, and it also allows your body to be well-fueled in time to start moving so that the blood sugar you need is actually in your bloodstream.
Eric Rimm, Sc.D., professor of epidemiology and nutrition at the Harvard School of Public Health, told Consumer Reports,
After a healthy breakfast, your blood sugar increases a little bit, but it will take a while for your body to absorb it.
Now, for those who don't break a sweat at dawn, it's not quite as important when you get your first meal on.
The jury is still pretty much out on the importance of breakfast first thing in the morning.
While there has been research that really does support the idea that breakfast is helpful for kids to focus and feel energized at school, the time that adults eat their first meal seems to vary based on both preference and habit.
But if you get up early to exercise, it is definitely something you should be doing one way or another, since you're going to be using a little more energy than if you were just, say, reading through Twitter over a cup of coffee. You need that nutritional fuel to support any kind of moderately intense activity, from early morning laps to even gentle yoga.
What you're looking for here is a sustained boost of energy to support you throughout your exercise. So, what you eat depends on the workout you're doing.
If you're taking an early, brisk walk with a little light weight training, snacking on something a bit smaller won't leave you feeling weak. Plus, if you're keeping the food light with something like a small yogurt, some toast, or a banana with a few nuts, you can indulge maybe about a half-hour before your workout, rather than a full hour.
However, if you're training for something more intense like a half-marathon, you might want to go for that decorated bowl of oatmeal or a protein-packed smoothie a good hour before you pound the pavement. And with these longer or more intense workouts, you'll also want to make sure you're eating something delicious and nutritious afterward, too.
All in all, when it comes to fueling before your a.m. workout, it's generally recommended that you keep your portion on the smaller side to reduce the chance of stomach upset or sluggishness. And go easy on yourself if it seems truly impossible to choke something down -- don't force yourself if you're not hungry.
If there's simply no way in the world you could stomach a morning snack, try something that might give you at least a little boost, like chocolate milk, a pack of flavored rice protein mix, or maybe even some grapefruit juice.