Speaking at The Purpose Summit from Campaign and PRWeek on Thursday, Nicola Simmons, PR and influencer manager at Ben & Jerry’s, also warned that brands risk being "left behind" if they don't act on a purpose.
She cited a comment from the brand's former chief executive, Jostein Solheim: "We're not an ice-cream company. We're an activism company that makes ice cream."
Simmons said: "That's a really important distinction to make because it's about the intentions in the heart of what we're doing."
Ben & Jerry's is famed for its campaigning work on progressive issues, including racial and gender equality, the environment and the plight of refugees. In August, the brand hit the headlines for its outspoken criticism of the UK Government's policy toward Channel crossings by migrants and refugees in small boats.
Simmons stressed the importance of "being in it for the long haul".
"That's another thing that will separate the people who are doing purpose correctly and the people who aren't. It's very easy to look at what's in the news that day and say: 'We're going to have a view on this,' but the minute it's out of the news it's not important to you any more – so the next time you go to speak up about something in the news, people are going to be going, 'Hang on a minute, didn't you just care about this other thing last week?'
"These changes happen over time. It's not instant gratification."
She gave the example of the Unilever-owned brand's campaigning work in support of Black Lives Matter – a movement she says it has supported for years – this summer.
"That put us in a position this year to finally be able to put our heads above the parapet and make our position known, but that was only possible through all the years of laying the foundation and helping people understand who we are."
Simmons stated: "Be wary of chasing the news agenda... As PR professionals, that's what we're taught – to be looking at what's trending, what people are looking at now, and jumping on it. But make sure you're doing that for the right reasons. And I would be very choosy about how and where you do that for maximum impact."
She also warned that it's "absolutely essential" for brands to have partners that know about the issues. Ben & Jerry's works with a number of NGOs and campaign groups, rather than charities.
Asked whether brands could be "left behind" if they "play it safe" and remain neutral on major issues, Simmons said: "I think naturally, because it is so important to people now.
"People want to spend their money in places that they know are using it responsibly, and so if you are one of those people [who doesn't embrace purpose], you are naturally going to get behind. But then what you risk if you just manufacture your purpose… you risk setting yourself back, because people see right through that also. So put yourself on that journey, but don't rush it."
The solution is not to have "a say on everything", Simmons added. "People won't expect that. It's having a voice that's standing for something."