Seasonal variation of body weight loss after bariatric surgery

ABSTRACT

Seasonal variations have been described in humans in several variables such as sleep, mood, appetite, food preferences, or body weight. We hypothesized that these variations could also influence the decrease in body weight rate in patients submitted to body weight loss interventions. Thus, here we tested the variations of weight loss according to the time of the year the surgery took place in a group patients (n = 1322) submitted to bariatric surgery in the Hospital Universitari de la Vall d’Hebron in Barcelona (geographical coordinates: 41°25ʹ41″N 2°8ʹ32″E). For the analysis, the percentage of total body weight loss (%TWL), excess body weight loss (%EWL) and percentage of body mass index loss (%BMIL) were calculated at 3 (n = 1255), 6 (n = 1172), 9 (n = 1002), and 12 months (n = 1076) after surgery. For %EWL and %BMIL a statistically significant seasonal variation was detected when the variables were calculated at 3 months, but not at the other times, with more weight loss in summer-fall. However, seasonal variations were not detected for %TWL (p = 0.09). The mean amplitude of the seasonal rhythm for %EWL was of 1.8%, while for the rhythm of %BMIL was 0.7%. Moreover, a second peak was detected in January–February modulating the seasonal rhythm of the two variables. Results confirm seasonal variations in humans and indicate that short term responses to weight loss can be modulated by the time of year.

KEYWORDS:

• Seasonality
• circannual rhythm
• body mass index
• weight loss

Conflict of interests

The authors have declared no conflict of interest.

Additional information

Funding

This work was supported by Ministerio de Sanidad y Consumo, Instituto de Salud Carlos III (ISCIII) [PI15/00190 to JP‒O PI15/00332 to JAB‒F] and FEDER Funds of the EU (Fondo Europeo de Desarrollo Regional: “Una manera de hacer Europa”).