All processed foods contain some food additives. They are used to preserve, sweeten, add flavour or colour to food, and to improve the quality and appearance of processed foods. Food additives include a wide range of chemicals. Some of these chemicals occur naturally in foods or are substances commonly used in the kitchen such as bicarbonate, pectin or food colourings. Others, like the sweetener aspartame, have been developed because they have qualities useful in food preparation or presentation. The term ‘food additive’ does not include substances added to improve the nutritional quality of food. All substances added to food are subject to national and international surveillance and regulation, including rigorous safety testing before they are approved for use by food manufacturers. In Australia, the safety of food additives is the responsibility of Food Standards Australia New Zealand, a federal government agency which works closely with state and territory governments and with other food regulatory agencies overseas. Food additives generally have a long history of safe use in food. Where safety is questioned, for example, in the case of new food additives, the additive is extensively tested in animals under carefully controlled conditions. This includes testing the potential of the food additive to cause cancer. However, while some additives may be toxic or show the potential to cause cancer when consumed at the very high levels administered in animal studies, there is no evidence that the same additives cause cancer at the very low levels consumed by humans in food every day. Processed food high in additives may also be high in sugar or fat which can contribute to weight gain. We know overweight and obesity increase the risk of cancer. You can lower your risk of cancer by enjoying a healthy diet including plenty of fruit and vegetables, being physically active every day and maintaining a healthy body weight.