Guava leaf tea lowers blood sugar levels because it's a part of the Mediterranean-style plant-based diet. Studies reveal that guava leaf tea has potent effects on glucose management, increasing insulin sensitivity and reducing postprandial hyperglycemia in experimental animal studies. One study showed that guava leaves work two ways - they reduce transit time (so our digestion is faster), but they also slow down the stomach contractions, so the absorption is longer. Meaning if we eat foods with high glycemic loads, drinks like guava can help us feel fuller for longer. Additionally, guava does have natural sugars in it, so it will raise insulin production, which will also help regulate our blood sugar levels after meals.