Indoor light= "Processed food" light. -Stripped of UV & infrared (IR), enriched in blue light, flicker (from LEDs). Sunlight = "Whole food" light. -UV+ full spectrum visible + IR, zero flicker. Eat whole foods and live in "whole light" if you want to be healthy.

Cheat days are a scam. Try quitting smoking by smoking a full pack one day per week and see how well that works. Choose to eat high quality foods consistently (unprocessed meat + plant foods) for 60 days without junk food and your life will be permanently better.