This is interesting.
I was just reading an article that states that if people want to avoid impulse buys at the supermarket, they should drink lemonade before they go shopping. Apparently, the brain uses glucose to fuel self-control. A study showed that people who drank lemonade containing real sugar rather than sweetener (which doesn't raise blood glucose) had stronger willpower while completing a task. Sub'haanallah. Among the many great things Umar ibn al-Khattaab (may Allah be pleased with him) is known for, one is his strong will power.
Also note the following saheeh hadeeth:
Narrated `Aisha (May Allah be pleased with her):
Allah's Messenger (ﷺ) used to love sweet edible things and honey. (Sahih al Bukhari 5431)