Post written by Sebastian Dobosz, with contributions from Michael Amlung.

New research has found that individuals diagnosed with obesity are consistently more likely to choose smaller immediate rewards over larger future rewards. The study, led by Dr. Michael Amlung, addictions researcher at McMaster University and St. Joseph’s Healthcare Hamilton, has been published in Psychological Medicine.

“While not all individuals diagnosed with obesity display this pattern of reduced capacity to delay gratification, at the aggregate level, the connection between this phenomenon and obesity is clear,” says Dr. Amlung. “These findings may help inform clinical approaches to weight management that increase individuals’ focus toward the longer-term rewards of weight loss.”

The study was a meta-analysis, combining findings across many previous investigations to detect consistent or inconsistent patterns of findings. It combined findings from almost 39 studies that enrolled over 10,000 participants.

The research team examined a concept known as delay discounting – which measures the degree to which delay to an outcome reduces it value. Delay discounting is typically measured by presenting choices between small rewards that are available immediately and larger rewards that are available after a set period of time. A steeper rate of delay discounting suggests a stronger preference for immediate gratification.

While research methods varied considerably across the previous studies, reanalyzing the data based on different methods did not appreciably alter the overall findings.

“The study suggests that, despite different experimental tasks, ages, and study designs, immediate reward orientation is robustly elevated in obesity,”

notes Dr. James MacKillop, co-author of the study and Director of the Peter Boris Centre for Addictions Research at McMaster University and St. Joseph’s Healthcare Hamilton. Other co-authors of the study include Dr. Iris Balodis, Jacob Jackson, Tashia Petker, also of the Peter Boris Centre for Addictions Research.

In terms of future research, Dr. Amlung notes that there are two important directions that have yet to be explored.

“There is emerging interest in dysregulated eating as a form of ’food addiction,’ with intriguing psychological and neurobiological parallels between eating and substance use.” says Dr. Amlung. “Our findings in obesity are particularly interesting given evidence that individuals with addictive disorders also consistently exhibit steeper delay discounting compared to healthy controls.”

Also important is examining the clinical applications of delay discounting in obesity. Delay discounting screening tools can identify which individuals have a reduced capacity to delay gratification to potentially help clinicians to deliver more personalized and effective treatment for obesity.

The full paper, published in Psychological Medicine, “Steep Discounting of Delayed Monetary and Food Rewards in Obesity: A Meta-Analysis”  can be viewed here free of charge for a limited time.