I couldn’t find the link in your post; is this the article?
Interesting notion! But what if your main willpower challenge is about eating sweets? 
Decision-making is one of my all-time WORST skills. It’s where I depart quite radically from the impulse-shopper picture that so many ADD’ers fit. I tend to get frozen very early on. The article suggests fatigue comes from making a large number of decisions, but I wonder if it’s possible to fatigue oneself over a single decision, if one agonizes over it long enough, as I do? It makes sense, if you think about the fact that to me, one decision has an infinite number of components; like dozens of little decisions that add up to the big one.
I do know that if I agonize long enough, the decision, if made, often still comes to a sort of “What-the-hell?” type response. I weigh all the facts, and then after a while I suppose I do get tired of that. Then I give up and just sort of go with my gut. Could have saved a lot of time just going there to begin with!