The 24-year-old singer has defended her older sibling - who was photographed wearing unflattering high-waisted jeans at a recent Florida concert with a seemingly fuller figure - insisting the comments about Jessica’s weight are "embarrassing and belittling".
She wrote on her blog: "I am completely disgusted. Since when did a woman's weight become newsworthy? How can we expect teenage girls to love and respect themselves in an environment where we criticise a size two figure?
"A week after the inauguration of US President Barack Obama and with such a feeling of hope in the air for our country, I find it completely embarrassing and belittling to all women to read about a woman's weight or figure."