Not long ago Carnie Wilson baked an Insta-worthy Oreo cake, garnished with cookies and whipped cream and dripping with a chocolate glaze. After proudly posting a picture of the finished product, she declined to indulge in it. “I still love to make decadent things, but I’m not tempted anymore. Now I have control.” For years sugar had the upper hand. “It was my kryptonite,” Wilson, 56, says. “It took over me.”