Yes, once you have studied the Soft style long enough to gain expertise in the fundamentals. This will require you to attend a minimum of two, one-hour sessions per week. At this point you can begin to pick up the pace and intensity of your Pilates routine and burn enough calories to make a noticeable change in the ratio of body fat to lean muscle mass.
Within the first five sessions (2 /1/2 weeks), you can expect to feel a positive change in your body. The tone and flexibility of your muscles will have begun to improve. You will be standing taller and moving with greater ease. In twelve sessions (six weeks), you may notice your clothes are a little loose and your friends and family will notice the difference. After forty-eight sessions (six months) you will have made a profound change in the shape of your body.
There isn't anything magical about the Pilates Method. The old adage about burning more calories than you consume will always be true. The fundamental principals of biomechanics incorporated in Pilates are the same as those found in many physical disciplines such as classical ballet, martial arts, and yoga, but the emphasis the Pilates Method places on the lengthening of the muscles while increasing their density will cause you to burn more calories at rest and make you look thinner.
It is worth noting our bodies are all about "adaptation". The degree to which your body changes is in direct proportion to the intensity of your workout. Simply put, if you are relatively comfortable while doing your workout, your body will have no need to adapt and change. An effective Pilates session will be challenging enough to encourage adaptation without being a struggle as this will just create tension and interfere in the creation of the Pilates body.
"If you will faithfully perform your Contrology exercises regularly, only four times a week for just three months, you will find your body development approaching the ideal, accompanied by renewed mental vigor and spiritual enhancements." - Joseph Pilates