Individual Differences in Within-subject Weight Variability: There's a Signal in the Noise

Humans show a high degree of stability in their body weights over time, a phenomenon explained by powerful, redundant homeostatic mechanisms. Nonetheless, human populations are also highly susceptible to develop epidemic levels of overweight in an obesogenic environment. Relatively little is known about the process responsible for the transition from remarkable weight stability to relentless weight gain. We have been studying individual differences in within-subject variability in body weights to learn more about this transition. This research has revealed that those who show greater WV over time are more susceptible to future weight gain; greater WV in those losing weight also predicts poorer weight loss maintenance. All the above findings continue to hold when baseline BMI and weight change over the WV assessment period are controlled. The relation of these newer findings to several trends in existing research was considered; these include the relation of weight cycling and morbidity, WV and eating/affective dysregulation, WV and medical diseases and WV and variability in daily energy intake. It appears that elevated WV per se is a risk factor for unfavorable clinical outcomes but little is known about the mechanisms accounting for these associations.