The artificial, non-saccharide sweetener Aspartame found in diet sodas is the culprit here. An Israeli study has shown it to increase insulin resistance and trigger fatty liver disease, which means there is a buildup of extra fat in the liver cells. Alcohol has also been linked to fatty liver disease. The organ’s job is to process everything we eat and drink, but too much fat will have an effect. The condition can also be brought on by excessive drinking. Alcoholic fatty liver disease is the earliest stage of other drinking-related liver problems. There are usually no symptoms.