Sugars are a form of carbohydrate found in a variety of foods, including fruits and vegetables. Since the dawn of agriculture and the industrial age consumption of sugar has increased rapidly, leading to an epidemic of obesity and other illnesses.
Like carbohydrates, excessive consumption of sugars can lead to type II diabetes, and cancer.
High sugar foods to limit or avoid include puddings, milkshakes, ice-cream, fruit juices, sugary soda drinks, cakes (especially with frosting), candies, fruit yogurts, fast foods, cereal bars, and commercial cereals. In this list, both the grams of sugar and teaspoons of sugar are given. 1 teaspoon is equal to 4 grams of sugar.
For more information see the article of high carb foods to limit or avoid, or see the nutrient ranking of 200 foods high in sugar.