The women's movement of the 1970s brought about significant changes in the family.
For the first time, women had reliable contraceptives, so family size decreased, women stayed on in the workforce after marriage and others returned to work, leaving children to be cared for by professional childcarers. This gave families more opportunity to eat out, as family size was small, less time was available for meal preparation, women had less energy after putting in a day's work and there was generally more money available to be spent on food with two incomes in the family. Dual-income families often have less time for preparation of food and more disposable money that can be spent on food. Thus pre-packed, partly prepared foods and ready-cooked meals are used more frequently than in past years.
Not all women returned to work and not all families were dual income, but the social changes that provided the growth in the fast food industry came to stay and were available for everyone.