Some risk factors for obesity become stronger the more overweight a person is, according to a study published Nov. 23 in the online journal PLoS ONE.
Paul Williams of Lawrence Berkeley National Laboratory in Berkeley, California found that certain risk factors lower education level, parental obesity, and high meat/low fruit diets produced a greater risk for excess body weight for subjects with a higher body mass index (BMI) than for those with lower BMI.
Based on these results, Williams proposes that environmental factors that result in little to no weight gain for lean individuals may have a much more pronounced effect for those who already have a high BMI, and this effect may help explain the recent large increases in obesity in many western societies.
Dr. Williams postulates that we have been witnessing is a positive feedback where as people gain weight they become more susceptible to obesity risk factors, which causes them to gain even more weight and become even more susceptible.
More information: Williams PT (2011) Evidence That Obesity Risk Factor Potencies Are Weight Dependent, a Phenomenon That May Explain Accelerated Weight Gain in Western Societies. PLoS ONE 6(11): e27657. doi:10.1371/journal.pone.0027657