Till today we don't have any principles that what to eat, when to eat, how to eat and how much to eat. But if we observe our ancestors they never used to put any food in their mouth in between meals. Even if we offer prasadam they'll accept it and keeps it aside up to next meals. Their breakfast lunch snacks and dinner used to have in fixed times only. Modern generation have timings for our duties but no time needed for snacks. Wherever whatever we will accept and we push it into our tank.
Say Stomach is Petrol Tank to understand much better. Every vehicle will have it's own petrol tank according to its necessacity human also will have. Our tank capacity is 2 litres. Load full tank once and wait until it get empty. Eat once until you feel satisfied and stomach is full wait until you feel real hunger. It is the normal principle.
But lets observe how it will be our eating pattern. Mornings everyone will have breakfast after going to office some occasion( Birthday marriage day whatsoever) someone will give small cake peice or some snacks. we throw it in our tummy. How it will work we can understand with simple example.
Think stomach=2 litres mixi jar. Can we grind a spoonful of soaked dal in it. When 4 Sharp blades which will rotate hundred times a minute can't grind how our stomach can grind. Lets go though another example to understand easily how our internal energies will be wasted. If we prepared food only for 4 members of our family unexpectedly 2 guests comes. Again we will cook extra food. We need to wait 2 more hours. All 6 members started eating 2 more guests comes in the half way. Again we must make them wait and 2 more hours. How much energy time and mood also will get distrubed.
Either it is small or big quantity whenever we eat 30% oxygen 50% blood 60% of our energy is needed to make the uneven food to glucose. Once digestion in intestines starts stomach can't produce all these for the small quantities. So food can't be digested properly. We will get Ulcers, Gases and Indigestion etc etc.
Same tensions and stress we are giving to our stomach and mind everyday we can't concentrate on our work. We can't perform perfectly. So have proper quantity at a time wait until you are hungry again. Whoever whatever don't get tempted because don't hurt by rejecting accept and keep aside.
One more disadvantage we can't get time to drink water if we eat or drink every one hour.