I'm in shape. I wear a size 6/8. I've worn my waist trainer for a year. It's a little bulky under most clothing but I work from home so I wear it for about 10 hours a day, seven days a week. I've noticed a difference in my waist. I now constantly get compliments on how small my waist is. It was already small but the trainer gives me more of the hour glass look I was wanting.
Bottom Line: No, I would not recommend this to a friend