What was eaten in North America up to the 1960s was fairly predictable, in large part to things like the Canada Food Guide which told people what they should eat. What changed was the lowering of airfares, allowing the average person to travel globally and try the cuisines of their travel destinations. Conversely immigrants were demanding food from their native countries, which in turn allowed locals to try these foreign foods. The food revolution has also spawned convenience foods - such as packaged and washed salads - and the A-list celebrity chef, who wields great influence over the general populous. The popularity of cooking has led to an increase in cooking programs and a growing importance in food styling for such things as photo cookbooks.