The purpose of this study is to determine what changes occur in body- and liver-composition during four weeks of low calorie diet in morbidly obese females

Preoperative weight loss prior to laparoscopic gastric bypass is desirable as this reduces liver volume and thus facilitates the visualization of the gastro-esophageal junction. Weight loss is often achieved through low-calorie diet (LCD); however the ideal duration of LCD treatment is unknown.

Morbidly obese female patients awaiting laparoscopic gastric bypass are recruited. They are, as all our patients, treated during four weeks with LCD to achieve a decrease in liver size. During this period they are examined on day 0, 3, 7, 14 and 28 after commencing LCD.

At each evaluation, body composition is assessed through bioelectric impedance analysis (BIA), liver volume and intrahepatic fat through magnetic resonance imaging. A questionnaire regarding quality of life and LCD-related symptoms is administered as well. At surgery two samples of subcutaneous fat and one sample of omental fat is taken.

We do not assign patients to different treatments, instead all are treated similarly according to our routine preoperative regimen.

Inclusion Criteria:

• Awaiting laparoscopic gastric bypass
• Residing near Uppsala

Exclusion Criteria:

• Weight above 140 kg
• Metal implants such as pacemaker or intracerebral clips
• Failure to understand or comply with study protocol

Morbidly obese females awaiting laparoscopic gastric bypass surgery