I feed my body with proper nutrition.

Most eating decisions were made at the shop, days earlier, by a version of you who was not hungry yet.

That is the leverage point. Willpower at nine at night in front of an open fridge is a weak and unreliable force. What is in the fridge was decided under far better conditions, well-fed and unhurried, pushing a trolley.

Change the shopping and the eating quietly follows, with no argument taking place at all. Less inspiring than discipline and considerably more effective. Nobody eats what is not in the house at eleven on a Tuesday night.