I do the majority of my training fasted (ie 8-14 hours since last I ate). I used to struggly wildly with working out before breakfast, but with some experience now I think training fasted is definitely superior [for my own needs, N=1, #YouDoYou].
Not only is it not uncomfortable, I feel _way_ better before/during/after working out.
Firstly: the food in your mouth is not used for your workout. You work out with food already digested and put in your muscles. Our biology is not precious, jungle-warrior neanderthals did turn into skeletal waifs if accidentally they hunted before noon without a BCAA-rich recovery shake. Nothing about morning training is energy, it is all habit, comfort, and hormones.
The primary issue, for most people (including me earlier), is that they train "before breakfast" and not "fasted". Important distinction. Hunger (and the hormone that causes it), comes in manageable 20-30 minute waves. If you do nothing it will pass. Most people take a banana, or some milk in their coffee, or a "little snack" before trainin. That breaks the fast. That is "break-fast", and it starts your body expecting food. So if you don't break your fast, you aren't exciting those hormones and insulin, so your body is ready to roll focused on the task at hand.
Secondarily is hormones. When you are fasted your body makes lots of great focus hormones. It also gives you extra HGH. Training also delivers HGH. Training additionaly delivers bombs of happy-hormones, and go-rip-the-world-a-new-one hormones. If you're fasted, you are more sensitive to those hormones, meaning you feel better. If you're fasted your low insulin also lets your body get as much fat-energy as it needs, so your energy levels can be amazing.
Outside of that is simple comfort and habit. The time your body expects food, the "engrained eating time", is adaptable. Having a lower baseline insulin, and a lower-carb diet, that minimizes "hangry" feelings and snack cravings will also be a huge help. Combine the two and you've got a recipe for insanely fun work outs with no hunger issues and better energy than otherwise.
Black coffee, water, and nothing caloric before training. It's night and day :)