Janet Jackson has gone from toned to tubby – again. Just recently, the 5′4″ Janet was proudly proclaiming that she’d lost 60 pounds and managed to keep them off for over a year. But as latest photos reveals, Janet – known for her yo-yo weight woes – appears to be hovering around 180 pounds now.

“Janet can’t maintain her lowest weight; it’s just not realistic,” says Janet’s friend. “She loses it when she needs to, like if she’s promoting an album, and then she allows herself to gain a bit.”

But if she has gained 60 pounds, it is hardly a bit. “The problem is that she’s slowed down her metabolism so much with yo-yo dieting that just about anything she eats will pack on pounds,” says Edward Jackowski, Ph.D., a NYC fitness and weight-loss expert who examined recent photos of Jackson.

But last July, Janet weighed only 120 pounds, thanks to help from a nutritionist, a trainer and a chef. That kind of diet roller coaster can be dangerous, experts note. “Losing 60 pounds and gaining it back can have serious consequences,” says NYC weight-loss specialist Stacy Title, M.D., who has not treated Janet.

So why did Janet let herself go this time? “She’s bummed out over her last album,” an insider reveals. “It was a failure, and Janet is seeking comfort in food.” Jermaine Dupri, Janet’s boyfriend could also be one of the reasons there’s more of Janet to love these days. “He thinks the extra weight is sexy!” her friend reveals. [via]