Social marketing applies marketing principles and techniques to influence behaviors that benefit society. It began in the 1950s with ideas around using marketing to promote public health and social issues. Government agencies, non-profits, and corporations now use social marketing. The "4 P's" of social marketing are product, price, place, and promotion. A recent study found many junk foods contain high levels of trans fats, salt, and sugar that can negatively impact health, especially in youth, contradicting nutritional claims made by companies. Strict adherence to product quality guidelines is important for foods and other products that directly impact consumer health.