In the United States, nonfunctional slack-fill is prohibited unless (1) it performs an appropriate function, such as protecting the contents of the container; (2) it is necessary because the machines used for enclosing the contents in the package require it; (3) it is the result of "normal product settling"; (4) the package performs a specific function that is inherent to the nature of the food and is clearly labeled; (5) the product is a food packaged in a reusable container where the container is part of the presentation of the food, e.g., a gift product; or (6) the manufacturer cannot increase the level of fill or decrease the size of the package, e.g., where a minimum package size is necessary to accommodate required labeling information, discourage pilfering, facilitate handling, or accommodate tamper-resistant devices. As a practical matter, the states are more active in enforcing the slack-fill requirements than the Federal government.

In the European Union (EU), the laws and regulations do not directly address this issue, but, rather, focus on ensuring that the actual contents of the package comport with what is declared on the label. However, in extreme cases, it is possible that an unusually low level of fill might be challenged on the basis of its potential to mislead the consumer under general laws prohibiting deception.