Make the healthy option the default option
Consider two scenarios:
1. You are stranded on a tropical island with abundant fish, vegetables, nuts and fruit
2. You have been given an unlimited budget in Las Vegas
In the first scenario, you are gonna eat "Paleo" whether you like it or not. In the second scenario, your default option is the buffet where you are exposed to all kinds of decadence beyond healthy choices.
These extreme examples are designed to underscore that the environment that we are in determines what our default options are; but...key here is that BOTH environments have default options - an option that consumes the smallest amount of willpower energy. Construct the right environment for yourself and you no longer have to expend energy to choose the healthy option.