Q: "I'm really interested in knowing what's in the food I eat, and would like to know if I am meeting my nutritional needs. Why do many food products not have Daily Intake labelling and should I trust the ones that don't?"
A: Percentage Daily Intake (%DI) only started appearing on food labels in 2006. It looks like a row of small curved boxes, called thumbnails, that contain numbers and percentages. These are meant to give you an easy graphic representation of how much one serve of the food contributes to your day's total intake.
This labelling is not compulsory. Some manufacturers choose to display it, while others don't. And of those that do, some display just the %DI thumbnail for energy (kilojoules), while others may include this as well as seven other nutrients: protein, total fat, saturated fat, carbohydrate, sugars, fibre and sodium. Breakfast cereals usually show three B vitamins and iron as well.
There can be many reasons that a manufacturer may not display this information. The obvious one is that it's expensive to redesign and reprint packaging so larger food companies are better able to absorb these costs than smaller businesses. Larger companies also have the technical staff to do the calculations.
Some manufacturers don't want to draw attention to an unhealthy product - would you buy a chocolate bar if you knew it gave you an entire day's intake of kilojoules? However, even if the %DI is not shown, you can work it out yourself.
Just divide the figures from the nutrition table on the back (which is required by law) by your whole day's intake to get a percentage. So something with 870kJ will give you 10% of the average intake of 8700kJ. You'll find your daily energy requirements on the nutrition information page in this website.