I have not seen research on the subject, but I expect that use of commitment devices can reduce decision fatigue. Steven King's story "Quitter's, Inc." gives an

I have not seen research on the subject, but I expect that use of commitment devices can reduce decision fatigue. Steven King's story "Quitter's, Inc." gives an extreme example of the efficacy of commitment devices, but a more mundane example might be making an agreement with a friend to pay them $100 for each day you cheat on your diet in the next week. If you're an honest person, you won't be tempted by the thought of cheating, since that slice of cake won't be worth $100 to you. You don't have to constantly decide whether to cheat on your diet; you only have to decide once per week (or per month, or however long of a term you set for your "commitment contract"). What's more, decisions pertaining to the use of commitment devices seem to be made by an aspect of you that looks out for your long-term welfare, not the part that simply wants a donut now.