Sweets, soda, fruit
Sugars are added to lots of processed foods.
Sodas are a major source. Fruit generally gets a pass (except in diabetics)because of the associated fiber content; fruit juice doesn't. Baked goods (desserts/snacks, goodies) are another obvious source. Simple sugars that we drink (or low fiber foods) tend to add weight more easilty, because we don't compensate as well by eating less at the next meal.