Behind the tourist strip there are a handful of local restaurants — sometimes called "meals hotels" in Kerala — that serve the traditional Kerala sadya-style lunch: rice, sambar, rasam, thorans (stir-fried vegetables with coconut), avial (mixed vegetables in yogurt and coconut), papad, and a small piece of fish or pickle. These are served on banana leaves and eaten with your right hand. The price is a quarter of what the cliff-top restaurants charge.
The backstreet eating scene in Kovalam is not extensive — this is a beach resort, not a food city — but it exists. Head away from the beach, behind the main tourist lane, and look for the small tea shops and meal stalls that open at lunchtime. The Vizhinjam village area immediately south has several local places where the fishing community eats.
Breakfast in these local places means parotta (flaky flatbread) with egg curry, or puttu (steamed rice cake) with banana and coconut milk. If you have not eaten Kerala breakfast before, this is the inexpensive and delicious version — far better than the generic Western breakfast menus on the beach strip.