Many friends believing in Vedanta, often argue with me on my strong view about having purity in food and water. They argue that, what is in this body? We are after all, mind and soul (आत्मा). Food does not matter!
Water flowing in the field takes the shape of the field. Similarly, our mind takes the shape as per our body in growth and sustenance state of life (ब्रह्मचर्य,गृहस्थ). If we don’t nurture it, your view of mind and soul, is nothing but delusion!
Quality Food (Grown by selfless farmer, stored by selfless vendor and cooked by loving family member) is essential, not only for survival but for ultimate goal of life i.e. self-realization.
Side note: We see so many cases of Autism in the west. one of many reasons is, food not nurtured by pure prana and mind. Mind and soul are powerful for all. It is supporting body that reflects their powers.
At the same time, in your वानप्रस्थ, mind is mature. Ideal if it has all ideal Sanskara. That is when you really don’t rely on body much.
For growing children and duty-bound grihasth, food is critical factor for performing वर्णआश्रम duties.