"I have an eating disorder so I have a hard time staying thin," the What I Like About You star wrote late Thursday, a day after several outlets published photos of her looking disheveled on the streets of New York on her 27th birthday.
"They write a news article about every tweet I write and I hate the pictures they choose," she wrote of the media. "They repeat what I tweet then add a bad photo."
The former Nickelodeon star wrote that the only stories she reads about herself is when she gives an interview.
"Don't trust what u read on sites!" she wrote. "Only use photos from my twitter when writing an article about me."
Earlier this week, Bynes claimed she had a doppelganger in New York that the media mistakenly thinks is her.
Bynes, who said she is retired from acting, has had troubled relations with her family in recent times. She moved from Los Angeles to New York City last autumn, saying she wanted to expand on her fashion career.