Green tea

Green tea is a calming beverage that can help you get going in the morning. Caffeine is present, which increases alertness and mood. One cup (240 mL) has just 35-70 mg of caffeine, which is roughly half the amount found in the same amount of coffee. It's also high in L-theanine, a chemical that promotes relaxation and may minimize the "jitters" associated with caffeine consumption. It may also help with mood and anxiety.

Finally, green tea contains epigallocatechin gallate (EGCG), an antioxidant that helps against chronic diseases such as heart disease, type 2 diabetes, and cognitive decline. More study is needed to determine whether it has a modest influence on metabolism.