In a large mixing bowl, combine flour, baking powder, cinnamon, and a pinch of salt. Whisk until blended.
In another bowl, whisk together eggs, sugar substitute, melted butter substitute, and vanilla extract until smooth.
Gently fold in the diced peaches.
Gradually add the wet mixture to the dry ingredients, stirring until just combined.
Fold in the chopped pecans.
Transfer the batter into the prepared loaf pan and smooth the top.
Bake for 50-60 minutes, or until a toothpick inserted comes out clean.
Allow to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.