Modern processed food products containing refined and natural sugars, carbohydrates, and proteins, especially when they contain gene modified (GMO) products. Fruits, grains and non-green plants also contain elevated deuterium levels. Other things that increase deuterium are exposure to artificial blue light (especially at night), EMFs from wireless devices and cell phones, supplements and pharmaceuticals. Natural, fatty food like grass fed meat, wild caught fish and seafood, green vegetables and nuts all have low deuterium.