Like many nutritional questions, this one does not have a definitive answer. After all, not all of us need the exact same thing as someone else. It is important to pay attention to how your body reacts when you attempt to fuel it. Like a car, properly fueling yourself can be what determines if you cross the finish line.
There is a middle ground when it comes to fueling up before a workout. You need nutrients to fuel you through your workout but eating too much or too soon before a workout can leave you feeling heavy, tired, or even nauseous. If you work out in the morning, you have to consider that your body has not taken in any nutrients for the entire time you slept. A good option for breaking that overnight fasted state would be a small, balanced meal. After a larger meal, waiting 2-3 hours before jumping into heavy activity may be a good idea.
Remember that we are all different and we react to things differently. Thankfully, we can adjust our bodies to new foods and new practices. What isn’t currently working for you may need to be tweaked or modified in some way.
Nutrition is sometimes a system of trial and error. Listen to your body, it will tell you what makes it feel and perform the best.