about 95% of packaged foods have added sugar, reaons for this is it makes the food taste better and to compensate for the extra sugar they use salt. To avoid all sugar altogether you can make everything yourself from mayonnaise to pasta sauce, so it is somewhat possible to avoide all sugar altogether however you'd need to be doing a lot of cooking.  David does recommend 10g of fructose a day, this is added sugar some products like for example yoghurt contain sugar on the label this is lactose and does not count towards your daily limit.  To avoid all types of added sugars, go for fresh foods and avoid processed packaged foods as much as possible.