Adding fresh items to the menu may be more difficult for fast food restaurants than for any other foodservice establishment.

Certain fast food restaurants, such as Wendy’s and McDonalds have recently added some new, fresh fruit items to their menu offerings. These additions are being made in an attempt for these quick service establishments to keep up with the increasing consumer demand for fresh and healthy options, but keeping pace with this demand is no easy feat for these establishments.

According to a recent report from the Chicago Tribune, it took over two years for Wendy’s to find farmers and to grow enough blackberries before the company could implement a national rollout of the company’s Summer Berry Chicken Salad. Likewise, it took McDonald’s over two years to source enough mangoes to supply the company’s 14,000 U.S. restaurants with enough fruit to launch the company’s new fruit smoothie. Even after two years, McDonald’s was forced to make compromises when it came to the particular type of mango that would be used in these fruit smoothies, because not enough of the specific mango that they desired could be provided to all of the company’s locations.

The trouble with working to keep up with the growing demand for fresh food items is that fast food companies do not generally have the necessary farm sources to introduce new fruits into the system, the Chicago Tribune reported. Additionally, it is rather risky for these foodservice establishments to introduce these new, fresh items to the market. Since it takes such great time and effort to source these items, it can be a devastating blow if the new menu items do not sell.

There are also some limits to which fresh items a fast food establishment can feasibly offer. Fruits such as peaches are too delicate and prone to bruising to be practical, while watermelon and cantaloupe would take up too much space to be stored and cut in the restaurant.

Making significant changes to fast food restaurant menus is risky business, and it takes a great deal of effort from the companies to make the right decisions when it comes to choosing which items to introduce to the menu and deciding how such items should be sourced.