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Publication - Professor Peter Rogers

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

    Citation

    Zimmerman, A, Mason, A, Rogers, P & Brunstrom, J, 2018, ‘Obese and overweight individuals are less sensitive to information about meal times in portion size judgements’. International Journal of Obesity, vol 42., pp. 905?910

    Abstract

    BACKGROUND:

    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.

    METHODS:

    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.

    RESULTS:

    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).

    CONCLUSIONS:

    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.

    Full details in the University publications repository