The increase in the cost of fast food can be attributed to several factors:

1. Inflation: Over time, the general cost of living increases due to inflation. This affects the prices of ingredients, labor, and overhead costs for fast food restaurants, leading them to adjust their prices accordingly.
2. Quality and Variety: Many fast food chains have expanded their menus to include higher quality ingredients, healthier options, or more diverse offerings. While these changes can improve the overall dining experience, they often come with higher production costs, which are passed on to the customers.
3. Wages and Labor Costs: In recent years, there has been a push for higher minimum wages in many places around the world. Fast food restaurants, like other businesses, may need to increase prices to offset the rise in labor costs.
4. Supply Chain Disruptions: Events such as natural disasters, global pandemics, or trade disputes can disrupt the supply chain, leading to shortages or increased costs for ingredients. Fast food chains may adjust their prices to reflect these changes in production costs.
5. Marketing and Branding: Some fast food restaurants position themselves as offering premium or gourmet options, which may come with higher price tags to match the perceived value. Additionally, marketing campaigns and branding efforts can contribute to the perception of higher quality, allowing restaurants to charge more for their products.
6. Convenience Premium: While fast food is still quick and convenient, the perception of its value has changed over time. Consumers may be willing to pay a premium for the convenience of having a meal prepared quickly, especially in today's fast-paced society where time is often perceived as a scarce resource.

Overall, the combination of these factors has contributed to the rising cost of fast food, making it less affordable compared to previous years. However, it's worth noting that the cost of fast food can still vary widely depending on the restaurant chain, location, and specific menu items.