I am at least 100lbs overweight, so your mileage may vary. In reading "The Art of Kilt Making" there is a blurb on how belt loops are sporran loops and about how putting a kilt belt through those will eventually deform the kilt.

Since reading that, I put my sporran belt through the loops, put my kilt belt on loosely over top. My belt more or less is a holder for my cell phone, knife, key keeper, flash drive, whatever.

Sometimes it does tend to creep up in back, I just push it back down.

My FK will ride down a bit without any belt, but only because I shrank a bit during the Jones, so I crank that down a bit. My UK stills stays up pretty well without a belt, so I just wear it almost snug on there.

But on my Stillwaters' I don't put it through the loops and wear it fairly loose. Working out so far.