The aim of this systematic review is to attempt to answer the question: Is substantial, stable and long-term weight loss a sustainable goal for obese adults?
We conducted a broad systematic search of non-surgical and non-pharmacological obesity treatment studies with the following criteria 1. Minimum three-year follow-up. 2. Five percent body mass lost. 3. No continued interventions in the follow up-period. 4. Prospective design. 5. Less than 75% attrition from the start of the follow-up period.
While the search revealed a very large number of published articles, only seven studies met the inclusion criteria. Several of the non-included studies report a majority of participants achieving satisfactory weight loss and little re-gain. However, these conclusions are often based on retrospective studies of a small portion of the initially sampled participants. Studies with continued interventions during the follow-up period are especially likely to achieve low rates of weight re-gain. In contrast, the seven high quality studies reviewed here demonstrate a trend of weight-regain, as measured by the all treatment groups combined. The mean percentage of weight loss was 8 %. Using linear spline regression we calculated a best fit line and found that the average rate of re-gain was 0.13% every month, reaching pre-intervention weight 53 months post intervention.
Although research efforts are abundant, we conclude that no robust weight loss studies have sufficiently demonstrated that substantial and stable weight loss is sustainable for adults without any follow-up intervention.