Instead of eating a ton of sugar, which is tempting to do when you're tired, try eating complex carbohydrates and protein. Sugar can give you a rush of energy, but then your energy will crash. Complex carbohydrates, on the other hand, offer more sustained energy, especially when you pair them with protein. For instance, try some natural peanut butter on whole-wheat bread or a piece of fruit with a slice of cheese. Dehydration can lead to fatigue. Therefore, staying hydrated will help keep your energy up. Try sipping on water throughout the day to make sure you get enough.  The Institute of Medicine recommends that men drink 13 cups and women drink 9 cups of water every day.  Other liquids can contribute to your water intake, such as juice and coffee. However, drinking too much juice can pack on extra calories and cause a sugar crash, so try to limit your intake. Also, though you can count caffeinated beverages, you shouldn't make them the majority of the liquid you drink in a day. Keeping something in your mouth, such as a piece of gum, can help increase your alertness. The best time for this type of trick is when you're in a meeting that you absolutely need to stay awake for.

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Write a summary of the previous text in Vietnamese:
Ngưng nạp đường. Uống nước là điều ưu tiên. Ăn kẹo cao su.