Pinterest has been flooded with weight loss spam in the second hacking incident since March, with the junk messages also spilling over to Twitter.
Users of the online image board were made to post messages advertising Asian fruit purported to burn fat, with others boasting about how much weight they had lost.
A spokesman for Pinterest said: "We were alerted to some instances of spam and responded by immediately placing impacted accounts in safe mode, and reaching out to Pinners as we solved the issue."
Back in March the website was plagued by pictures of scantily clad women after suffering a similar breach, in violation of the website’s prohibition against sexually explicit images.
Hackers were thought to be visiting external sites featuring the social media button "Pin this", and inserting malicious code swapping the desired content for spam.
In 2012 security firm McAfee found toolkits online providing hackers with all they needed to target Pinterest with spam, allowing them to easily scam users with promises of free gifts or shocking content.
"Such toolkits make it very easy for scammers to start their own scam sites and become functional cybercriminals with a minimum of skills and time," said Hardik Shah, senior research engineer at the company.
"They need only change a couple of simple things, such as URLs, and they are ready to go."
The news also adds to a growing controversy in IT security about users’ lax attitude to passwords, with a number of profile attacks highlighting the danger of reuse across several websites, as well as the dangers of passwords susceptible to brute force attacks.
"We’re constantly working on ways to keep Pinners safe through reactive and proactive steps, as well as educating them on the importance of using complex and unique passwords," Pinterest added.
