Our stomach has changed over the course of time and metabolism changed because of our food habit. Earlier hunter gatherer humans would go days without food and then eat larger meals. Just like wild animals did. But as we grew into food producers, when we shifted to agriculture we were having sufficient amount of food at our tables. Probably the concept of breakfast would have started in that agriculture era. Also raw foods which early humans took was replaced by cooked food. This also led to shrinking of digestive tracts as cooked food was comparatively easy to digest. Anyways the breakfast is an important meal of the day which gets your day started.

Should we eat heavy or light breakfast?
Breakfast can be depending on the work you perform. For hardworking folks it is recommended to have light breakfast and ideally for desk work or light work heavy breakfast. Now it might seem unusual, but to be honest to digest heavy breakfast you will need a less stressed environment. Our body does work in this fashion because digestion needs energy. You might have heard some people complain about acidity and other gastric problem, it is due to this basic science.
Well hardworking folks can compensate light breakfast with heavy lunch and a few minutes of rest. That way it will keep you more healthy.
What should be a light breakfast?

A light breakfast comprises of honey, bread slices and a boiled egg. A whole wheat flat bread with some vegetables will be ideal but it will take some time to prepare. A quick breakfast is oatmeal or milk porridge. Serve it with a cup of coffee. Pour some water in the pan and put in some crushed grains keep stirring until you get the desired thickness. Don’t forget some seasonal fruits. Now you are good to go.
Making a heavy breakfast.

A heavy breakfast should be good enough to stay with you till midday. Bacon or Lamb salami with a few poached eggs if you have a good appetite . Spaghetti with chicken breasts and a glass of juice. Fried Flat breads with a chunk of scrambled eggs. A half plate of chicken rice would be a great breakfast. Add some sandwiches if you are traveling long hours for work. All this takes time to prepare but it would be worth it.
Conclusion
Whether it be a light or heavy breakfast you can choose on your own. To keep your bowel healthy remember to add more fibre like banana and sweet potatoes. Also, drink a good amount of water an hour before breakfast. This habit will help in digestion keeping piles and constipation at far. Work hard eat well and everything will be just fine. I would not recommend you coffee in the morning but later in the day would be perfect. Stay healthy.