Obese and overweight individuals are less sensitive to information about meal times in portion size judgements

Annie Zimmerman, Alice Mason, Peter Rogers, Jeff Brunstrom

Research output: Contribution to journalArticle (Academic Journal)peer-review

3 Citations (Scopus)
402 Downloads (Pure)



Obesity is related to a tendency to discount the future. Information regarding inter-meal interval (IMI) allows meal planning. We sought to assess how obese, overweight, and lean people select portion sizes based on the length of an IMI. We hypothesised that individuals with a high BMI would discount information about the IMI. In addition, we investigated how reduced sensitivity to IMIs relates to monetary temporal discounting.


Participants (lean, n=35; overweight, n=31; obese, n=22), selected lunchtime portion sizes in response to information about the timings of their next meal. In seven trials, the time of the IMI was systematically manipulated, ranging from ‘right now’ to ‘8 h’. Participants then completed a monetary temporal discounting task. BMI was included as a continuous measure. For each participant, we conducted a linear regression of portion size on IMI to yield a gradient that reflected reduced sensitivity to future meal timings.


As expected, participants selected larger portion sizes in response to a long IMI. Consistent with our hypothesis, individuals with a high BMI discounted information about the IMI (β=−3.49, P=0.015; confidence interval (CI) 6.29 to −0.70). Monetary discounting also negatively predicted BMI (β=−8.1, P=0.003; CI=−13.43 to −2.77), but did not correlate with IMI sensitivity (P>0.05).


These results are the first to demonstrate that temporal discounting operates in planning from one meal to the next, and is more prevalent in obese and overweight, relative to lean individuals. Participants with a high BMI discounted concerns about potential future fullness and hunger in the IMI. Our observations might begin to explain associations between obesity and irregular meal timings or help to form the basis for a targeted intervention that promotes future thinking in meal planning.

Original languageEnglish
Pages (from-to)905–910
Number of pages6
JournalInternational Journal of Obesity
Issue number4
Early online date16 Nov 2017
Publication statusPublished - Apr 2018

Structured keywords

  • Brain and Behaviour
  • Nutrition and Behaviour
  • Physical and Mental Health


  • Obesity
  • Meal times
  • Impulsivity
  • Delay discounting
  • Meal planning
  • Portion size
  • BMI


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