Public health campaigns and industry-supported changes in our food supply have obviously failed to control the epidemic to date. However, customized life style modification programs (LSMP) comprising diet, physical activity and behavioral therapy (a set of principles designed to help patients achieve their goals) induce weight loss of 10% of baseline body weight after 16 to 26 weeks of intervention . Long-term weight control is then facilitated by an appropriate weight-loss maintenance strategy such as continued patient-therapist contact (whether provided in person or by telephone or e-mail). This strategy allows patients to stabilize at an average of 5% and 3% loss of baseline body weight after 1 and 2 years, respectively. Numerous reports have concluded that this modest weight loss contributes to important health benefits.

However, the high dropout rate during weight-management strategies presumably means that treatment is mainly effective in highly motivated patients, as the highest success rates are likely to be reported among study completers. Many individuals appear to conclude that the benefits of weight-management strategies are not worth the cost (i.e. time, money, and continued unrewarding efforts). This underlines the critical need to implement new, practical and affordable strategies to induce and maintain weight loss that can be achieved by most patients.

The main objective of this study is to test the hypothesis that a 3 week intensive course of spa therapy can reduce the weight (and/or BMI) of overweight or obese patient at 14 months (BMI from 27 to 35).

Spa therapy, or mineral spring water therapy, is a 3-week LSMP that has been shown to be sufficiently effective to control overweight and obesity to be approved and subsidized by French national health insurance. However, good quality scientific evidence is still required to support the benefit of spa therapy. An unpublished pilot study conducted in 2004, in several French spa resorts, showed that an additional 25% decrease in BMI was obtained for overweight and obese individuals enrolled in spa therapy as compared to individuals receiving classic weight management (-1.4 kg/m² and -1.05 kg/m2 respectively). However, no scientific conclusions can be drawn in the absence of relevant methodological and clinical information. This multicenter, controlled trial was designed to obtain sufficient statistical power to assess the benefits of spa therapy based on an evidence- based medicine approach.

The primary objective of this study was to assess whether a 3- week course of spa therapy is effective to achieve sustained weight loss over a period of 14 months among overweight and obese individuals

Inclusion Criteria:

• Both sexes, more than 20 years and less than 70 years old patients with overweight (BMI>27) or obesity (BMI<35). Available for a spa treatment during 18 days, and a follow-up period of 14 months
• Voluntary to participate to the study,informed consent form signed after appropriate information
• Affiliation to the social security system or equivalent

Exclusion Criteria:

• Previous spa therapy for weight problems
• Pregnancy
• Major eating disorders (compulsive over eating)
• Poor french proficiency
• Involvement in another clinical trial
• Other contra-indications to spa therapy (severe general weakness, inflammatory bowel disease, cirrhosis, severe disability, psychosis and dementia, or Immunodeficiency, cancer in progress).
• Refusal to consent
• Refusal of spa treatment