In a large bowl, dissolve sugar in warm water and then stir in yeast. Allow to proof until the yeast forms a creamy foam, about 5-10 minutes.
Mix in salt and oil. Add flour one cup at a time, mixing until dough comes together.
Turn dough out onto a lightly floured surface and knead for 7-8 minutes until smooth and elastic.
Place dough in a greased bowl, turning to coat. Cover with a damp cloth and let rise in a warm place for about 1 hour, or until doubled in size.
Punch down dough. Divide in half and shape into two loaves. Place into two greased 9x5-inch loaf pans.
Cover and let rise again for about 30 minutes, or until dough has risen about 1 inch above pans.
Preheat oven to 350°F (175°C). Bake for 30 minutes or until golden brown and loaves sound hollow when tapped.
Remove from pans and let cool on wire racks.