Can you use up all of your willpower?

For the past 6 months or so, I have not been able to stick to my eating plan. I've gained back about 25 pounds of my total 75 pound weight loss. However, I felt like I needed a break from counting calories and worrying about food all the time. I literally said to myself, "I just want to give my willpower a little rest." Then, I see on the news a study where psychologists found that people have a limited amount of willpower. In the study, participants were divided into two groups. One group was told to not eat cookies placed in front of them and not laugh at a funny movie that was shown. The other group could do what they wanted. When the two groups' willpower was tested again, the first group had less willpower than the second group. So in terms of weight loss, does this mean that we should deliberately give our willpower a break? When it comes to dieting, falling off the wagon is never good, but instead of falling off the wagon does this mean that maybe we should deliberately jump??