How we change what others think, feel, believe and do
When your will is sapping and you are finding it harder to decide, then pause and eat or drink something with glucose in it. Sports energy drinks are a good example, although anything with sugar in it works. Even plain sugar dissolved in water works fine.
You can also take some glucose if you know you are going to have to make some important decisions soon (within the hour), just to top yourself up.
A team working on strategic plans stops every couple of hours for a sweet drink and a biscuit.
A person has a cup of sweet coffee before going shopping, to help stop them buying things on impulse that they do not really need.
When you think and mentally exert yourself, your brain uses glucose from the blood. In fact most people spend around half their time resisting desires to do things they know they should not do. The exhaustion of self-control is known as ego depletion.
Sugar is an easy way of ingesting glucose and is quickly absorbed, giving you not just physical but also mental energy. This sudden benefit is sometimes called the 'sugar rush'. Beware also that this may be short-lived and your energy may drop almost as quickly as it increased.
Note that artificial 'low calorie' sweeteners, such as in diet colas, do not work. It has to be glucose, which generally means sugar although natural forms such as honey are also just fine. Glucose also appears in a suprisingly wide range of food.
The importance of glucose was discovered by Roy Baumeister and colleagues when investigating the idea that indulging in pleasure builds will. They fed subjects milkshakes and the control group a tasteless goop. Surprisingly, both groups increased their willpower. Later, they found that the key ingredient was glucose. The latter experiment fed one group lemonade sweetened by sugar and the control group lemonade with artificial sweetener. This time, only the sugar group increased their willpower.
In a study of the Israeli parole board by Danziger and colleagues, just before the midmorning break, where the judges ate a sandwich and a piece of fruit, prisoners had about a 20 percent chance of getting parole. Immediately after the break, there was now around a 65 percent chance of getting parole. All it took was a bit of fruit to refresh the tired brains of the parole judges.
Gailliot, M.T,. Baumeister, R.F., DeWall, C.N., Maner, J.K., Plant, E.A., Tice, D.M., Brewer, L.E. and Schmeichel, B.J. (2007). Self-control relies on glucose as a limited energy source: Willpower is more than a metaphor. Journal of Personality and Social Psychology, 92, 2, 325-336
Danziger, S., Levav, J. and Avnaim-Pesso, L. (2011). Extraneous factors in judicial decisions. Proceedings of the National Academy of Science USA, 108, 17, 6889-6892