The four main food groups are proteins, starches, vegetables and fruits. We should be waiting at least half an hour for one food group to digest before consuming another type of food group, so that limited putrefying and fermentation of food occurs inside our intestines. Various foods require digestive juices and enzymes, and require different lengths of time to be digested.
Thus, eating excess hard-to-digest foods from too many different food groups in the same meal , is the primary reason we may not be having at least one good bowel movement every day. And such resultant constipation should be a signal that our body accumulating more and more toxic build-up daily. Ideally, when we were originally hunter-gatherers, we would only eat one type of food as we found or hunted for it, and it digested well. But our modern day supermarket shopping allows us to mix many different food groups together in one meal.
There is an old saying that states..."Eat like a peasant in order to live like a king!" Eating from the kings’ table often conjures up images of all kinds of healthy delicacies. But many kings and queens in medieval times did not live to ripe old ages due to their over-indulgences of meats and other delicacies—whilst some of the peasants around them did, mainly by surviving on smaller portions of mostly plant-based diets. And it is both the overabundance of food and the mixing of too many different food groups together in the one meal, as each food group requires different stomach acids for proper digestion. It is such a condition that also ultimately causes the final state of waste in our colon to become putrefied or fermented: This is the highly undesirable state that allows increased toxicity of our bodies.
I have included a 'food combining' chart below for those who are extremely serious about their health. It is only meant as a helpful guide and virtually impossible to follow everyday in our modern society, but helpful to know, nonetheless.