Wearing a waist trainer can help reduce the amount of food you eat and also remind you to tighten your core muscles, which very well may lead to more permanent results. However, for the most part, size reduction is temporary – although results may be semi-permanent in cases of extended waist training. This is most commonly observed with the prolonged use of heavy-duty corsets. While a heavy-duty corset may eventually reposition floating ribs and even shift internal organs, resulting in a smaller waist, your body will most likely return to its normal shape a few months or years after you stop wearing it.