Systematic review of the effects of pandemic confinements on body weight and their determinants

Pandemics and subsequent lifestyle restrictions such as ‘lockdowns’ may have unintended consequences, including alterations in body weight. Understanding the impact and the mechanisms affecting body weight is paramount for planning effective public health measures for both now and future “lockdown”-type situations. This systematic review assesses and the impact of pandemic confinement on body weight and to identifies contributory factors. A comprehensive literature search was performed in seven electronic databases and in gray sources from their inception until 1 st July 2020 with an update in PubMed and Scopus on 1 st February 2021. In total, 2,361 unique records were retrieved, of which 41 studies were identified eligible: 1 case control study, 14 cohort and 26 cross-sectional studies (469, 362 total participants). The participants ranged in age from 6–86 years. The proportion of female participants ranged from 37% to 100%. Pandemic confinements were associated with weight gain in 7.2%–72.4% of participants and weight loss in 11.1%–32.0% of participants. Weight gain ranged from 0.6 (±1.3) to 3.0 (±2.4) kg, and weight loss ranged from 2.0 (±1.4) to 2.9 (±1.5) kg. Weight gain occurred predominantly in participants who were already overweight or obese. Associated factors included increased consumption of unhealthy food with decreased intake of healthy fresh fruits and vegetables, changes in physical activity, and altered sleep patterns. Weight loss during the pandemic was observed in individuals with previous low weight, and those who ate less and were more physically active before lock down. Associated factors included increased intake of fruits and vegetables, drinking more water and consuming no alcohol. Maintaining a stable weight was more difficult in populations with reduced income, particularly in individuals with lower educational attainment. The findings of this systematic review highlight the short-term effects of pandemic confinements. Learning from the “lockdown” experience is fundamental if we are to prepare for the next wave; a holistic, reactive, tailored response is needed involving multiple providers.