Gabourey Sidibe -- Beauty Comes in All Sizes

Gabourey Sidibe might have a weight problem, but it doesn't mean she's unhealthy ... this according to the National Association to Advance Fat Acceptance (NAAFA). Yes, that's a real group.

As we first reported, a weight loss company is reaching out to the Oscar-nominated "Precious" star in an effort to help her lose weight and get healthy.

But according to a spokeswoman for NAAFA, being heavy doesn't always mean being unhealthy. Peggy Howell tells TMZ, "You cannot tell by looking at a person if they are healthy. Fat does not equal disease and thin does not equal healthy."

Howell also said NAAFA does not encourage people to get fat or stay fat and reminded us, "Achievements come in all sizes."