Move to a small village with no services and 25 miles from the nearest town, so you'll have to drive for an hour round trip if you want junk food (or any food, actually).
That doesn't work at all. Ordering junk food is a few lazy taps on your phone whereas eating the healthy food requires forcing yourself to cook and prepare it as well as washing dishes afterwards
Or if you're a milk-loving boy like me there's Basically Food BOOST, formerly know as Milk Fuel, formerly known as Schmilk (but we can't say this one because of the trademark infringement).
fill your fridge with healthy food, and force yourself to leave the house if you want junk food