Imagine a world where women wouldn’t have to ask their friends and partners, “Do I look fat in this?”

That’s exactly the world that fashion expert Charla Krupp is trying to turn into a reality. The best-selling author of “How Not to Look Old” is back with a second book called “How to Never Look Fat Again” and she is sharing some of her top secrets to dressing thinner with Fox411.com.

A former magazine editor and “Today Show” stylist, Krupp says one of the most important things a woman can do for herself is to shop for the size and shape she is at this second.

“Women tend to put on big baggy clothes to hide their bodies and conceal what they don’t want anyone to see,” Krupp told 411. “But when you wear sizes that are too big for you, you look bigger than you are … You have to wear something that shows your body shape, because you might not drop another pound, but that doesn’t mean you shouldn’t feel good.”

Krupp said her main goal was to ensure that women feel good about themselves, even if they aren’t at their ideal weight.

And the biggest thing keeping from real women from feeling their best? That would be arm jiggle, back fat, muffin tops and other frightening terms that plague the majority of us as we shop for jeans, tops and dresses.

A big reason for this, Krupp tells 411, is that the average woman is wearing the wrong underwear. In fact, she says that 50 percent of looking ten pounds thinner is wearing the proper undergarments.

“There’s no way around it,” she said. “A woman MUST go to a store where she can get fitted. You can’t be a mom of four who hasn’t been bra-fitted since your first child. And on that same note, get rid of every pair of underpants that doesn’t do anything for you. You should be wearing things that will smooth you out every single day.”

But aside from investing in underwear, a fat-free wardrobe doesn’t have to cost a fortune. After all, Krupp says even stars like Jennifer Lopez and Charlize Theron make fashion mistakes, like their Oscars dresses.

“Don’t buy a whole new wardrobe because you already probably have everything you need in your closet, it’s just hidden away,” Krupp said. “Keep your closet full of fat-free clothes.”

Krupp even provides readers with a list of the “100 Most Fattening Things You Can Wear,” like down vests, acid-washed jeans and Crocs. “You have to go through your closet and assess each piece. If you have to wonder if you look fat in something, get rid of it.”