Seasonal weight variation patterns in seven countries located in northern and southern hemispheres

Abstract

The digital revolution of information and technology in late 20th century has led to emergence of devices that help people monitor their weight in a long-term manner. Investigation of population-level variations of body mass using smart connected weight scales enabled the health coaches acquire deeper insights about the models of people's behavior as a function of time. Typically, body mass varies when the seasons change. That is, during the warmer seasons people's body mass tend to decrease while in colder seasons it usually moves up. In this paper we study the seasonal variations of body mass in seven countries by utilization of linear regression. Deviation of monthly weight values from the starting point of astronomical years (beginning of spring) were modeled by fitting orthogonal polynomials in each country. The distinction of weight variations in southern and northern hemispheres were then investigated. The studied population involves 6429 anonymous weight scale users from:(1) Australia, (2) Brazil, (3) France, (4) Germany, (5) Great Britain, (6) Japan, and (7) United States of America. The results suggest that there are statistically significant differences between the models of weight variation in southern and northern hemispheres. In both northern and southern hemispheres the lowest weight values were observed in the summer. However, the highest weight values were noticed in the winter and in the spring for northern and southern hemispheres, respectively.

Weekly, seasonal and holiday body weight fluctuation patterns among individuals engaged in a European multi-centre behavioural weight loss maintenance intervention

“…This process refers specifically to the process of removing the overall trajectory of the time series thus centering the body weight and leaving the variability. Detrending of body weight data was conducted to account for the potentially confounding effect of weight change on patterns of variability as suggested previously [11,15]. For weekly and Christmas analyses, the body weight data was detrended by fitting a LOESS (locally estimated scatterplot smoothing) regression (S2A Fig) to each participant.…”

“…Similarly, holiday (typically Christmas) weight gain has been well documented with increases in weight in the region of 0.4-1kg being reported consistently across the UK, Europe, North America and Japan [13]. Seasonal fluctuations across the year are often less pronounced and more inconsistent, though may be characterized by a decrease in weight during the summer and an increase in the winter [14][15][16] which has been shown in both Northern and Southern hemispheres [15]. Indeed, it is possible that in each of these cases, short-term increases in weight partially contribute to long-term weight gain.…”

“…For inclusion in the Christmas analysis, at least 4 weights were required in the 30 days prior to and after Christmas (defined as the 25th of December). These minimum criteria were designed to improve the accuracy of statistical smoothing as suggested previously [15] and also demonstrated previously by our group [34]. Inclusion in one sample did not prevent inclusion in another.…”

Seasonal and subtype differences in body mass index at admission in inpatients with anorexia nervosa

“…Seasonal variations in body weight have been consistently reported. In European and North American countries, body mass index (BMI) is on average higher in the winter than in the summer (Mehrang, Helander, Chieh, & Korhonen, ). This pattern has been found both in the general population (Visscher & Seidell, ) and in overweight adults participating in a behavioral weight loss intervention (Fahey, Klesges, Kocak, Talcott, & Krukowski, in press).…”

Humans in the cold: Regulating energy balance

“…Although there would seem to be an increase in EI with CE in humans, the data are scarce and inconclusive at best. Furthermore, studies pertaining to seasonal variations in environmental temperature have shown that body weight increases in the winter, although this is associated with increased EI and decreased physical activity. The purpose of this review is to provide a comprehensive overview of available literature on the effects of CE on EI and appetite from both animal and human studies, as well as compensation in response to chronic CE.…”