Janet Jackson shows off her svelte figure on the cover of Prevention‘s July issue, on newsstands May 29. Here’s what the 46-year-old singer had to share: On shedding the pounds: “Health was always a concern. When I gained weight in 2005, my nutritionist was very worried. I was close to having diabetes. Even when I lost it [and] then gained quite a bit back, there was always the thought of heart disease … Knowing I have these problems with body image, I ask my friends and family to tell me when I’ve lost too much. Because I will continue to pick on myself like all other woman do, and say, ‘You need to [lose] more here, more there.’She looks real fab for a woman her age..Nice going.