Many of you would know that it is Sun’s light/heat that governs our metabolism. As the sun rises in the morning, its light (even indirect) falls on our pineal gland (the third eye) activating the entire body and mind. By noon when sun is right above the head, we are most active with our blood circulation at its maximum speed and as sunlight begins to recede, it begins to slow down. That’s how by late evening we feel sleepy if we are healthy and enough blood is reaching our brain. Thus, apart from ensuring that we don’t eat those foods that reduce blood from our brain (except as medicine), our food also should be in line with the amount of heat ( Pitta) present in our body which in turn depends upon the position of the Sun vis-a-vis our location on earth and other factors like exercise etc. So, as a thumb rue, in the morning when our energy reserves are less after overnight fasting, we should begin our day with seasonal fruits which provide energy/nutrients and get slowly absorbed in the body due to presence of fiber in them thereby not thickening the already slow moving blood. Our lunch should be heaviest when our metabolism is at its peak (fastest blood circulation). And our dinner should be lightest and latest by sunset so that even less pitta (heat) is able to digest it properly, else heavy and/or late dinner is bound to create toxins which slowly but surely would begin to block our blood circulation.
This also means that our act of giving a kick to our mind and body in the morning with bed tea/coffee is the worst thing that one can do to oneself. The act of waking up should be as slow/subtle as the act of sleeping. We don’t sleep suddenly in the night. It gets slowly induced due to receding sunlight.