No, you only get a maximum of 15 syns a day to spend on treats (like crisps, sweets etc), and other indulgences (like tomato ketchup, mayo on your dinner etc). The main body of your food is meant to be made up of free and superfree food and healthy extras. As kikarro posted above the number of syns in a food is calculated according to whether it has any free food in it. If it doesn't have any then a rough rule of thumb is 20 calories per syn. This thread is very informative -