The aim of this study is to evaluate if an internet-based CBT (Cognitive Behavioral Therapy) programme for weight stability after LCD (Low Calorie diet) treatment for obesity, can reduce weight gain and improve weight stability, self reported health, pain, eating behavior, fatigue and mood.

Adults with obesity and health problems in primary health care are invited to be part of the study. The geographical area is Orebro county which has in all 29 primary health care centers. Population is 276 000, and according to population studies around 15% of the adult population has a BodyMassIndex (BMI) over 30, which is characterized as obesity according to WHO.

Specific objectives are;

• To evaluate if internet-based CBT treatment after LCD improves weight stability after 1 and 2 years.
• To evaluate if weight loss improves metabolic parameters such as HbA1c, blood glucose, Cholesterol, Low density lipoproteins (LDL),High density lipoproteins (HDL) , triglycerides (TG) and Bloodpressure (BP)
• To evaluate weight loss influence on quality of life, body pain, eating behavior, obesity related problems, fatigue and mood, and to see if CBT program for weight stability also improves these factors
• To evaluate if LCD treatment is a possible treatment for obesity in ordinary primary health care

Patients taking part in the study, undergo a 12 week period of Low Calorie Diet (LCD) treatment, followed by a 12 week reintroduction to ordinary food. During this period the patient has contact with the primary health care nurse and doctor. After 24 weeks of treatment, the patient who follows the study is supposed to have lost around 10% of initial weight.All patients losing more than 7% weight during the first 24 weeks, are randomized to either ordinary follow up (group 1) or an internet-based CBT programme for weight stability (group 2). All patients in the study are followed at 1 year by doctor, and at 2 year by nurse visit.

Patients are recruited in an ordinary primary care setting in Primary care centers in Orebro County. All Primary care centers in the area (26) are invited to take part in the study.

Patients are given brief information at ordinary visits at doctor, nurse or physiotherapists, or by written information announced at the health care center. Before going into the study they need a doctors visit to pass the inclusion and exclusion criteria. The study starts at a nurse visit where the patient gets written information about the LCD treatment and the protocol.

After 24 weeks in the study, all patients with weight loss of 7% or more are randomized into two groups.

Group 1, keep their contact with the nurse at the primary health care centre, and gets a written prescription of physical activity, which is followed by a visit at 36 weeks.

Group 2, gets a code for the internet-based CBT programme. They go into the programme at home, and follow the programme which has the goal of weight stability and contains strategies of meal plans, portion controls, physical activity planning, and cognitive strategies of thinking and goal setting. During this programme there is an opportunity to "chat" with CBT therapists via the internet, concerning the programme and its challenges. No personal meeting with therapist is included.

At 1 year in the study both groups meed with doctor at primary health care center and at 2 year there is a nurse follow up at the same center.

At baseline, 12 weeks, 24 weeks, 1 year and 2 years several validated instruments are used to follow patients wellbeing due to:

• Quality of life (Short Form -36, SF-36)
• Obesity related problems (Obesity related Problems Scale version 3 OPv3)
• Mood (Mood Adjective Chek List MACL)
• Self reported pain (Brief Pain Inventory Short form BPI-SF)
• Eating behavior (Three Factor Eating Questionnaire- Revised 21 Items TFEQ-R21)
• Fatigue (Multidimensional Fatigue Inventory MFI)

We also investigate the patients experiences of the treatment, how they manage to hold on to the diet, and how it effects their motivation for ongoing lifestyle changes. For this we use a study specific instrument.

Inclusion Criteria:

• BMI > 30 with health problems and willingness and motivation to make lifestyle changes.
• Access to the internet and the ability to read and understand written information in swedish.

Exclusion Criteria:

• BMI < 30
• Excessive eating disorder problems (screening forms are used)
• Severe heart failure (New York Heart Association (NYHA) class III-IV)
• Moderate or severe COPD (Chronic Obstructive Pulmonary Disease) (FEV% <50)
• Uncontrolled asthma (hospitalization or more than twice requiring inhalation treatment on health care site last year)
• Pregnancy and lactation
• Type 1 Diabetes
• Serious liver dysfunction (ALT value more than doubled, women> 1.5 μkat / L, men> 2.2 μkat / L)
• Former Gastric bypass surgery or other weight reducing surgery