Blend a protein shake, buy the ingredients before hand and it takes maybe a minute or two or to get a healthy filling breakfast in
I found that using a protein smoothie in the morning is my quickest, fastest and healthiest option. It only takes 2 mins, you can prep the night before and blend and you’re out the door. It will likely be trial and error to find the protein shake that you prefer but I buy unflavored so that I can mix it with coffee or fruit to bring some variety in the AM
A to-go breakfast is effective and quick! Fill your bottle with some soya milk, prepare a sandwich right before sleeping, and all you have to do is to pick it up before leaving the house.
I think it depends on your routine. Also, eating a good breakfast is not just about eating a lot or eating extremely slowly, but feeling nourished. Wake up earlier or try researching nutritious and fast foods for breakfast, such as dried fruits like nuts, chestnuts, raisins, etc. Try to vary more and you will see results day in and day out.
I make sure I prepare something the night before when I know that I need to leave my house in a rush. Preparing meals ahead had help me out a lot.
You could have it prepped and ready to go. E.g. make breakfast muffins (with eggs or with oats) for the week and then grab one and a small pot of yogurt every morning, maybe a piece of fruit too. Another suggestion would be to make a smoothie or overnight oats the night before so it's ready for you in the morning.