Yes, the 2-bite-rule should only be applied when you are thoroughly in control of your appetite! Don't even try it if you're famished! Have some veg/meat/cheese/eggs first to take the edge off, THEN have that one spoonful of lasagna and one of fudge brownie. (Still only two bites...)
The whole low-carb/keto lifestyle requires a bit of fencing with both an intrinsic gravitation toward calorie dense foods and a strong advertising industry that does its best to exploit that tendency.