Want to have more self-control? A wide range of studies (see here for examples) by Florida State psycholgists (e.g., Roy Baumeister, Brandon Schmeichel and Nathan DeWall) suggest that you can increase your self-control in a surprising way - by drinking lemonade!
These studies show that:
1) When people practice self-control, they have reduced glucose levels.
2) Low levels of glucose are associated with worse performance on difficult (but not easy) tasks that require self-control.
3) Consuming drinks with glucose (like lemonade) makes people have higher levels of self-control on a variety of tasks.
In one study testing point 1, glucose levels were measured, and then participants were randomly assigned to either watch a video normally, or to watch a video with words flashing in the corner of the screen that they had to ignore looking at. The act of self-control (not looking at the words) was enough to reduce glucose levels among participants.
In a study testing point 2, participant's glucose was assessed, and then they had to again show self-control by ignoring words in the corner of a screen during a movie. They then had to perform a Stroop Task. Participants who had lower glucose levels after exerting self-control performed worse on the Stroop Task (glucose and self-control were significantly correlated after the self-control movie task).
In a Study testing point 3, participants drank lemonade (or a control group drink) and then were reminded of their own death (or a control topic), which past research suggests impairs self-control. After this, they had to complete a series of word fragment completions (e.g., complete G R A _ _ with a word). If self-control is impaired by death salience, they should complete less word fragments in that condition. And, if lemonade provides self-control, drinking lemonade should protect against this. That is exactly what this study found.
In sum, self-control relies on a supply of glucose. When performing difficult tasks, you might want to drink some lemonade (or some other glucose drink) to aid your performance.
Lemonade: a vital cog to self-control.