Since losing excess weight is beneficial for improving health and fitness levels, it would be surprising to discover that it may be the source of health problems such as back pain. Developing back pain with weight loss may be the result of several factors. Identifying and correcting the factors will help diminish back pain and discomfort.Your spine and the muscles surrounding it provide support, stability and mobility. Your lower back and abdominal muscles provide a base of support for your spine, holding your body upright. In addition, they contract and stretch to bend and rotate your spine. Discs are located between the bones in your spine and act like cushions to absorb impact on your spine.Your muscles, bones and connective tissues are subject to weakness and degeneration. Factors such as aging, smoking and unhealthy lifestyle typically contribute to spinal problems through structural weakening. Structural problems, including spinal deviations, may affect alignment and posture, resulting in back pain. Muscular imbalances and decreased bone density affect movement, causing injuries and spinal problems. Incorrect exercising, lifting and carrying can strain your back, contributing to pain and discomfort.Weight loss is the result of decreasing the amount of calories you consume. A decreased amount of calories may result in an inadequate amount of nutrients for your body. Weight loss that results in a significant amount of water and mineral loss contributes to decreased bone density. Weaker bones can cause spinal misalignments and result in pain. Weight loss as the result of increased physical activity can lead to overtraining, improper mechanics and overuse injuries, including back problems. Body-fat percentages are reduced with weight loss. With reduced body fat, your body loses the cushioning effect of body fat in places such as your buttocks and hips. Reduced cushioning in your buttocks may cause discomfort when sitting on hard surfaces and may affect spinal alignment.Determining the type of back pain is the first step in diminishing it. For structural problems such as spinal deviations, improving muscular strength in your supporting muscles such as your abdomen and lower back improves alignment. Correcting improper form when exercising, lifting and carrying helps reduce pain from improper body mechanics and movement. Replacing reduced body fat with increased muscle mass will provide a cushion for sitting on hard surfaces.Back pain with unexplained or unintentional weight loss can be indicative of serious medical issues, such as infections and disease. Individuals experiencing these symptoms should consult a physician.