I happen to just have read most of the literature on this topic. The first part of the article is well substantiated, but the second part (about training your willpower) seems to be based on very little data. So far I've been able to find only one source, I think, in Muraven/Baumeisters "Does Self-Control Resemble a Muscle?"). The title is phrased as a question for a reason. Afaik no one knows if your newly found willpower will last and if so, how long.
I, too, am very sceptical of the second claim (about training your willpower). I have pushed myself as far as I can over long periods of time without noticing any increase in the size of my willpower muscle.
Mouni Sadhu (kind of a new-age crackpot, but a very to-the-point and convincing writer) wrote about this in his book Samadhi, which I think was published in the 50s. He talked about starting off restricting small aspects of your behavior (like eating dessert), keep at it for 8 weeks or so at which point it becomes habitual, and then move onto tougher restrictions. But, if you start to ease back into the things you've already conquered, believing that "oh i'm strong enough to do this in moderation now", your tower of willpower will collapse. I don't know his methodology for getting this info, but it probably wasn't rigorous.
from my experience (quitting drinking), you can hack willpower with mantras. reminding yourself of something every morning and night, in a motivational way, keeps it alive as a goal over the months-long slog. the tricky part is forcing yourself to do this...so one of your mantras should be "i love saying mantras."
I've noticed that the most effective way to get a programming project finished is to just let everything else slide for a few weeks: paying bills, exercising, being social. Probably not a very healthy way to live in the long run, though.
"Other activities that deplete willpower include resisting food or drink, suppressing emotional responses, restraining aggressive or sexual impulses, taking exams and trying to impress someone."
Can't for the life of me think why you'd want to do any of those things. Gotta have some fun somewhere ...