Obese Americans are finding churches, synagogues and mosques can promote exercise, healthier diets and improved self-images, new research indicates. But many severely overweight women, paralyzed by real and perceived prejudice, find it easier to be “couch-potato saints” than to go out in public for the spiritual and social support that can lead to better health. One new study found obese women were more likely to affiliate with a religious congregation, but less likely than other women to attend services or participate in congregational activities.