Full-body detoxification, or fasting, does not cause malnutrition when practiced safely, although the health and weight-loss benefits are debatable, according to WebMD. Pregnant women and people with poor nutrition or compromised health conditions should not practice fasting.
Short-term fasting has a limited impact on nutrition because the body can use stored energy for one or two days. A water- or juice-based diet can result in some weight loss, but medical experts note that the benefits are usually temporary, says WebMD.
Some experts feel that the body has sufficient, natural cleansing abilities, while others believe that the highly processed, modern diet causes unhealthy toxins to build up in the body over time. Fasting has been practiced for centuries in many cultures, but the proven health benefits remain unclear, as of 2015, according to WebMD.