That last dinner after saying "I'm starting my diet tomorrow"

I'm really tired of fooling myself. Every Monday, I start with hope, but by the evening, that diet falls apart. Tonight, I supposedly ate everything I wanted for the last time, and I tell myself I'll definitely start tomorrow, but deep down, I don't even believe myself. I genuinely think there's such a thing as food addiction because when I crave something, I can't stop myself. Do you think this is an illness?