Margarine used to be pink in some U.S. states  

due to laws and regulations put in  place to protect the dairy industry.

Margarine was invented in the 19th century  as a cheaper alternative to butter.

When it first became popular, the  dairy industry felt threatened by  

its lower cost and the potential  loss of market share. As a result,  

they lobbied for laws that would make  margarine less appealing to consumers.

One such law required margarine  manufacturers to color their  

product pink, a shade that was not  naturally associated with butter.

The intent was to make margarine  look unappetizing and undesirable,  

thereby discouraging people from buying it.

This regulation was eventually repealed,  

but for a period of time, pink  margarine was sold in some areas.

It's worth noting that not all margarine was pink  during this time, as the laws varied by state.

However, the pink coloration is a  notable example of the lengths some  

industries would go to in order  to protect their market share.