Preheat the oven to 350°F (175°C) and grease a loaf pan.
In a medium saucepan, combine the lentils and water. Bring to a boil, then reduce heat and simmer until the lentils are soft, about 15 minutes. Drain any excess water.
In a large bowl, mix together cooked lentils, whole wheat flour, baking powder, salt, and olive oil.
Pour the batter into the prepared loaf pan and smooth the top.
Bake in the preheated oven for 45 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.