If you suffer from back pain and are more than 10 pounds above your ideal weight, losing that weight may significantly reduce the amount of pain you are experiencing. According to Dr. Andre Panagos, co-director of The Spine Center at New York’s Presbyterian Hospital, “Although research on weight loss and back pain is minimal, in my clinic, every single person who loses a significant amount of weight finds their pain to be significantly improved.”

The muscles, tendons and ligaments that work to keep the spine upright and aligned can be put under a great deal more stress when there is more weight for them to support. Even simple everyday tasks such as reaching over to put an item on your pantry shelf can be harder on your back when those supporting muscles have extra weight to maneuver. Losing weight reduces the extra strain on your spinal muscles. 
Although no studies have conclusively shown that being overweight is the cause of back pain, being overweight or obese can contribute to back pain in a couple of ways. First, for those who are overweight, short periods of exercise often cause fatigue, shortness of breath and difficulty breathing, which can discourage people from exercising. This can indirectly cause pain in the back because inactivity and lack of exercise are major contributors to back pain. Insufficient exercise leaves your back muscles, stiff, weak and out of condition. Second, excess weight, particularly around the stomach, pulls the pelvis forward and causes an excess curvature in the vertebrae of the lower back, causing pain and stress on the muscles and supporting structures of the back.
Another way in which excess weight can contribute to back pain is by the development of sciatica or piriformis syndrome caused by a herniated disc. When vertebral discs have to carry an excess load, they can become herniated. Imagine each vertebral disc as a small water balloon. The more weight that presses down on it, the more it bulges, sometimes tearing and losing fluid. This can cause the space between the vertebrae to narrow, leading to possible nerve compression.
Extra body weight can also cause arthritis of the spine. The American Obesity Association advises that weight loss can lower the risk of osteoarthritis, as those with a body mass index (BMI) more than 25 are at greater risk of the disease.
If you are overweight, consider starting a low-impact exercise program to slowly and gently lose weight. Walking, swimming, or other forms of water exercise can be a way of exercising that will not stress your muscles, tendons and ligaments while giving you the physical activity you need to get you started on the road to weight loss. Studies have shown that sticking with a regular exercise program can help to reduce episodes of back pain and prevent or lessen any future episodes.