Absent minded or mindless eating - these are the things we often take for granted and don't bother to remember. After all why bother? Typical American has at least 3 x 365 meals a year. That freight train seems like an impossible logistical problem for any one person to manage. It has to be mostly on instinct or we would have given up long ago.
And yet we have a cultural heritage that attempts to define and guide us, tells us when to eat, whats appropriate to eat. Even advertises to us from television and media to encourage us to "Take care of" the business of keeping ourselves healthy and happy consumers.
History Magazine has an excellent overview of how its changed over time. I highly recommend it.
What Time is Dinner?
The article traces the evolution of the "three squares a day" notion, as if we were mechanical beasts.
We may be a type of machine but I tend to think we're also a product of biology that adapts and would (given the choice) prefer a much more attentive host to its needs.
For example, in our traditions we don't really take into account (at least not explicitly) the microbes in our digestive and absorption system and their secondary benefits or detriments to our overall health.
A common belief today is that over consumption of six sided sugars (Table Sugar) can lead to dental and gum disease which can lead to high blood pressure, heart disease and strokes. On the other hand there is emerging thought that five sided or "pentose" sugars like Xylitol can act like a natural "antibiotic" and stave off or prevent all sort of bacterial disease and infections.
There is strong evidence we all carry a secondary "digestive" system not unlike that in herbivores which "post processes" and continues to digest what we cannot digest directly into secondary by products in the gut which may cause or stave off things like cancer... or reset our circadian rythyms to be in tune with the seasons. The importation and availability of foods from around the world may confuse and offset the seasonal cycles and perceptions of our own personal interior worlds.