Start the day off right by drinking a glass of water as soon as you wake up. Glassman suggests adding a slice of lemon for flavor because it will also help detoxify the liver, which plays a key role in our long-term health by metabolizing the foods we consume. Why water? As she explains, since our bodies are 50 to 70 percent water, the most common reason that people are sluggish in the afternoon is due to dehydration. So, not only start the morning with water but continue to drink it throughout the day. As Nestle says, water gets her vote over sugary drinks: "Don't drink your calories!" Keeping a reusable water bottle at work will help to ensure a constant supply is there as needed.