President George W. Bush referred to himself years ago as “the decider.” Just like presidents before and since, his days were filled with myriad decisions – many with great complexity and global implications. On a somewhat smaller scale, but perhaps a similar level of complexity, organizational leaders like you find their days filled with choices and decisions. From the smallest (“Do I have time to write that memo?”) to the largest (“Should we fund that project?”) decisions, people rely on you to make choices throughout the day that benefit the organization. Add in the decisions you make in the hours before and after work (“Do I go to the gym or go out for dinner?”). Apparently, good decision making is based more on state of mind than personality trait, and you can take steps to ensure you are at your best.

Until recently, many of us thought good decisions were the product of wisdom and knowledge. Those are certainly key ingredients in decision making, but research indicates factors like time of day and glucose levels also influence our ability to make sound decisions. Ignoring those factors can lead to decision fatigue. This is the term used in the book, Willpower: Rediscovering the Greatest Human Strength. Written by social psychologist Roy F. Baumeister and John Tierney, science columnist the New York Times, the book is highlighted in an essay by Tierney for the New York Times Magazine.

Decision fatigue is a biological consequence of having to make too many decisions. Surprisingly, decision size or level of importance does not matter; all the choices we must make throughout the day add up. Unlike physical fatigue, we are not aware of decision fatigue. Our brains just plain get tired throughout the day, which compromises willpower and can deplete self-control. This results in consequences like rash decision making or the inability to make any decision at all. Those consequences do not exemplify the hallmarks of a great leader!

But there is an antidote to this fatigue and it lies in what Tierney calls the “power supply.” Further research yielded unexpected results indicating glucose reversed the effects of depletion in the brain. The brain doesn’t close down when its power source is gone. Instead, it keeps working and craves refueling. When we crave, our decisions become focused on immediate reward rather than long-term outlook. This short-term perspective is not what most of us expect from our leaders. Don’t reach for that candy bar, though. Brain glucose levels are best sustained by eating nutritious foods.

Here are three things you can do to ensure optimal decision making, as suggested by Tierney:

1. Be rested: Structure your life to conserve willpower. Avoid back-to-back meetings that call for multiple decisions. Set up routines (like working out every morning) to limit your choices.
2. Be fed: Eat nutritious food to maintain glucose levels. Although sugar from candy will help in a pinch, it is not a sustainable source of glucose. Instead, eat protein and vegetables.
3. Be aware: “The best decision makers,” claims Baumeister, “are the ones who know when not to trust themselves.” Consider the time of day, how demanding your schedule has been, and what you’ve had to eat and when.

Follow these suggestions to avoid decision fatigue and be the best decider you can be!