I’ve written many posts over the years on nutrition and one of main questions I get is regarding breakfast. I am asked about once a week, ‘What, if anything, should I eat for breakfast when I workout early in the morning?” Well, the answer isn't as simple as it may seem as it really depends on lots of factors, including workout type, intensity, duration, and food tolerability. There are many approaches to how we ‘break (our) fast’, with all ends of the spectrum represented when it comes to this question. Some swear by fasted workouts, others absolutely have to eat a solid breakfast before getting into it, others just grab what they can. Most of us fall somewhere in between these extremes.
So let's address what actually happens when we sleep, when we eat, and when we exercise. When we are at rest, our body shuts down many of its systems to focus on the process of repairing and rejuvenating various structures of the body. This happens most efficiently when we are in deep sleep (another plug for the virtues of sleeping in over burning the candle at both ends in order to squeeze in a workout). When we wake, our body’s systems begin to come online. If we are morning exercisers, we immediately ask it to start working relatively hard, many times without a lot of time to warm up. All of this takes energy, and depending on the last time we ate (possibly 8-14 hrs prior) we are most likely deficient in the calories *most* necessary for the body to work at optimum capacity.
Without getting into the pros and cons of intermittent fasting (only eating during a very tight time window on the day, usually leading to fated workouts), if we are engaging in lower intensity exercise, most people can get by without eating if the exercise session is less than 60 min or so and/or are at lower intensities. This is because at lower intensities, the body’s primary energy system is aerobic and the fuel source is fat. However, when the intensity picks up, the body’s primary fuel source changes to dietary carbohydrate, which is stored in the body as glycogen- of which the body has a very finite supply. This energy system is known as anaerobic.
If people are going to do higher intensity work OR longer duration efforts, the general recommendation is to eat something prior to the workouts. So, what do we eat?
As a general rule, if the intensity for the prescribed workout is high intensity (think HIIT training, speed work, hill sprints, FTP bike work, OR it’s a hot/humid day, then we want to shy away from lots of fiber and fat for our breakfast. We want to trend toward something lighter, and easier on the stomach, with a low fiber content and medium to high on the glycemic index (generally carbohydrates). Examples of this could be applesauce, a banana, or a tortilla with honey. If it’s going to be a long, slow run on a cold, dark morning, then a runner might afford to have a bit more fat or fiber for their breakfast meal. This could be something like oatmeal with nut butter, yogurt with fruit, or a bagel with jam. We can get away with a touch more fat and fiber because the stomach shouldn’t get as bogged down due to the blood leaving the stomach (going to the surface of the skin due to heat, or the limbs due to intensity of effort).
But let's say you’re going to do some really high intensity work; something that really pushes the limit. This could be hill or track sprints if you’re a runner, or 30/30 VO2 max intervals on the bike, or tabata workouts in the gym. When this is the case, I tend to keep the breakfast really light, small in quantity, but with a higher glycemic index. My favorite for this type of effort is apple juice, Gatorade, or even a gel with water. At this intensity, the body will burn through its glycogen stores at an alarming rate, so it’s important for most people to have at least a bit of carbohydrate in the system or risk becoming nauseous or light headed.
Again, as with all things nutrition related, everyone is different. Trial and error is still the best way to determine what is right for each person. However, knowing what energy systems are used- and therefore what fuel source is optimum- for each type of workout, is a good starting point. Determining what’s the right thing to eat- or not eat- for breakfast is a critical step to maximize not only your morning training sessions but your nutrition plan as a whole. As always, if adhering to the ‘basics’ several weeks doesn’t work, consulting a certified professional is the best step to create the optimum nutrition plan, including the perfect ‘breakfast of champions’ for you.