I hope you finally know for sure that skipping breakfast is NOT a good idea. Saying that you don’t have time to eat in the morning before you start exploring the city or take a train/plane somewhere else is bullshit.
But do you know what you should eat for breakfast? I bet it is not easy to get something healthy so I would like to give you some ideas.
I personally prefer to have oatmeal with fruit and nuts for breakfast. As weird as it may sound, I got this habit a few years ago when I was in Scotland for the first time and I got oatmeal with berries in my B&B. I fell in love with it the very first day. In Slovakia where I am from people don´t tend to eat oatmeal but bread with vegetables, cheese, sausages and ham which I never really liked. So when traveling, I adapted a healthier habit and then also made it a habit when visiting Slovakia.
I try to carry oatmeal with me when I travel as a pack lasts for a few days. If I cannot make oatmeal with fruits (my favorite ones are bananas and berries) and nuts, honey and cinnamon, at least I get oats with soy milk. Every night before going to bed I already look forward to my oatmeal in the morning. It is very easy to prepare.
If I am in a hotel/hostel with breakfast, I try to get cereals with milk and fresh fruit/fresh juice for healthy breakfast. If possible I finish it with a whole-grain bread with cheese and eggs to get some protein too.
Remember, egg whites are always healthier than whole eggs. If I have hardboiled eggs, I never eat the egg yolks as they are full of unhealthy cholesterol.
You can also eat fresh fruit salad, just chop fruit you love. These are sold in many countries at the street or also train and bus stations/airports so no excuse when traveling.
Smoothies/protein shake/freshly squeezed juices (many of those bought in packs in stores are not the best choice, always check out what they contain) can be also easily purchased around the world in case you cannot make your own.
If you are a cheese lover, than the best cheese you can get for breakfast is protein-filled cottage cheese. Plain you can eat with fruit, cinammon and honey or the herbal one even with ham. Also tofu cheese is a great option. It can be prepard with eggs and vegetables, for example.
A soy yogurt or a low-fat yogurt could be a possibility instead of oats. Add granola, any whole-grain cereals, fruit, honey and seeds to get a lot of energy. Please always check cereals before buying them as those chocolate ones, coloured ones and all those containing fruit already contain a lof ot sugar too. Better buy plain whole-grain cereals and then mix them with fresh/frozen/dried fruit (some dried fruit also has a lot of added sugar, so be careful too).
As well, I love adding sunflower seeds, sesame seeds, chia seeds, ground flax-seeds (they have to be ground to make the nutrients available as whole ones just pass through your body and get out without anything), buckwheat or millet.