Willpower: Rediscovering the Greatest Human Strength contains so much useful information that I’m exploring the key points of this book in separate blog entries. In my first post on it, I described how self-control or willpower is likened to a muscle that can be exhausted. The more you use it throughout the day, the less strength you have.
So how does the body replenish willpower? According to Baumeister and Tierney, the answer is glucose. When we digest food, our bodies produce glucose molecules that enter the bloodstream providing energy to the cells of our muscles, brains and various body systems. No glucose, no energy, no willpower
This phenomenon is born out again and again in research. For example, scientists in Finland studied convicts being released from prison. The researchers were able to predict –with 80% accuracy– which convicts would go on to commit violent crimes simply by monitoring their blood sugar. Other studies found that persons with hypoglycemia seem to have a harder time concentrating and controlling negative emotions. Diabetics can have more problems with impulsivity, alcohol abuse, anxiety and depression than non-diabetics. In all cases, self-control is more elusive when glucose levels are low.
So where does the body get the necessary glucose? Fruits, starchy and sugary foods top the list. Think about what you crave when you blood sugar takes a dip… Sweet drinks, sugary snacks, and often chocolate come to mind because they provide a quick hit of glucose.
Women might appreciate knowing that Willpower also gave context to the cravings and weight gain associated with PMS. Following ovulation, a woman’s reproductive system uses extra energy (glucose), leaving less available for the rest of her body. To counteract the shortage, sugar can seem pretty irresistible at this time of the month. However, healthy low-glycemic foods like nuts, veggies, and fish also provide what’s needed and have been shown to alleviate PMS symptoms.
An interesting bit of advice from the authors to parents is that if your child is sick when it’s time to take the SAT, they will almost certainly be better off taking it the next time it’s offered. The self-control needed to sit for hours solving math problems and choosing vocabulary definitions just isn’t there when a virus is sapping your glucose.
Finally, sleep is also vital to healthy glucose levels and resulting willpower. When we are sleep deprived, our body’s ability to process glucose is impaired. We all know how overwhelming upcoming decisions and tasks can feel at the end of the day or in the middle of the night. Remember it will all feel infinitely more doable in the morning. More rest, more glucose, more willpower, less stress.