Viveka

Yesterday we saw the qualities one should develop. Today let us see the first one. Viveka. Shri Ramanuja interprets this as pertaining to food. Let us go on look at it the same way. Viveka is to use our discriminative intellect as to what we eat. Why is it so important? Because it not only gives energy to body but also to the mind. It influences the three gunas and feeds them.
The gunas as something you're born with. They are the sattva, the rajas and the tamas.
At any given time. Only one of them will be dominant. The other two will be quite. What is dominant at any given time, is influenced by the food that we eat. Therefore we must try to eat food that is saatvic.
Food items made with liberal spices and salt promote rajasic qualities. That which is bitter, sour and very hot are also rajasic. Generally those which are very tasty are rajasic.
Food items that are few days old, those that are spoilt, meat, and the remnants at the dinner table are tamasic.
Food items that are mild in taste, that which is a little sweet are saatvic.
In general, what is tasty to the pallate doesn't do good to the mind. Rajasic food agitates the mind, and we became emotional. Tamasic food makes you sleepy and our actions become dull. Therefore, if we aim to be peacefully happy we should always prefer saatvic food.

आहारशुद्धौ सत्त्वशुद्धिः सत्त्वशुद्धौ ध्रुवा स्मृतिः ।

āhāraśuddhau sattvaśuddhiḥ sattvaśuddhau dhruvā smr̥tiḥ |

This means if the food is pure, your mind is also pure. Cleansing of the mind instills godliness in it.