I've had to do this alteration on almost all of my jeans and pants. Everything fits but the waist and gaps in the back. Belts don't help because the gap is still there. Expensive jeans and even the ones that have "no gap waist" still don't fit right. I personally can't afford $100 jeans, but I did see a website for PZI jeans which say they fit for this kind of problem. I find that I can buy cheap jeans and alter them this way for the perfect fit. (WalMart jeans even) Don't even try using elastic in the back--it's bulky and really unattractive--believe me I've tried.
Finally learned to fix this problem properly. It's a bit of work but if you do some basic sewing or know someone who does, it's well worth your time and effort! I wait until I have several pairs to alter and do them all at once while i have the right color thread in my machine.
First of all, it helps if the jean doesn't have a "yoke" back, as that adds quite a bit of bulk when you sew, though it's still possible. Also, be sure the pockets aren't already close together--this method will bring them a little closer. So this depends on how much you need to take in.
I suggest buying a "jean a ma jig" at the sewing store, to help your machine go over the bulky seams. Also, purchase a denim needle. There is even have thread that is varigated blue which works nicely on darker jeans.
Use a seam ripper to remove the stitching of the waist band. You may have to remove the stitching at the top of the waistband as well--depending on the type of band, if it's a 2 piece waistband or just a folded over one. I only remove stitching for a few inches on either side of the center seam--the more I've done this alteration, the less I've had to undo at this step.
Remove the belt loop if there is one in the center back, as well as the tags--I don't put tags back because they bug me anyway.
*note: as you remove the seams, make sure to check how everything was sewn together originally, to help you put it back together.
Remove stitching down the back seam, how far down depends on how far down your jeans need to be altered. You will hve to remove the "flat felled seam" in the back to do this (if there is one) This is the kind with the 2 rows of stitching that lays nice and flat.
Pin and sew the back seam to fit your waist (remember if you have to make it 1 " smaller, you only need the seam 1/2 " smaller--1/2 " on each side of the seam will make it 1 " smaller.
I always try them on again at this point. If it fits well, stitch the "flat felled seam" down so it looks like the regular seam. I personally don't worry that the thread is perfect because I always wear shirts that cover this area (I don't tuck in shirts).
Open the waistband and take it in so it will fit the new seam. How you do this depends on the type of waistband. I like to taper my waistband so that it's smaller at the top of the band, down to where it joins the jean (where your new seam is). This is more comfortable for me but may not be necessary for everyone.
Now you're ready to add the waistband back to the jeans/pants. Sew carefully and use the "jean a ma jig" to help you go over the thick seams (like in the center, especially if there is a flat feld seam). Sew everything to match the way it was originally.
Sew the belt loop back on if you needed to remove it. Sew the tags back if you want.
I do this for jeans as well as dressy work pants. I don't have to wear a belt which is much more comfy for me as I have a bit of a tummy.
Hope this helps anyone who has this very common problem.
Yvette Poulin, October 2007
