Portion size influences intake in Samburu Kenyan people not exposed to the Western obesogenic environment

Kevin P. Myers*, Jeffrey M. Brunstrom, Peter J. Rogers, Jon D. Holtzman

*Corresponding author for this work

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

2 Citations (Scopus)
140 Downloads (Pure)


For people in the modernized food environment, external factors like food variety, palatability, and ubiquitous learned cues for food availability can overcome internal, homeostatic signals to promote excess intake. Portion size is one such external cue; people typically consume more when served more, often without awareness. Though susceptibility to external cues may be attributed to the modernized, cue-saturated environment, there is little research on people living outside that context, or with distinctly different food norms. We studied a sample of Samburu people in rural Kenya who maintain a traditional, semi-nomadic pastoralist lifestyle, eat a very limited diet, and face chronic food insecurity. Participants (12 male, 12 female, aged 20–74, mean BMI = 18.4) attended the study on two days and were provided in counterbalanced order an individual serving bowl containing 1.4 or 2.3 kg of a familiar bean and maize stew. Amount consumed was recorded along with post-meal questions in their dialect about their awareness of intake amount. Data were omitted from two participants who consumed the entire portion in a session. Even though the ‘smaller’ serving was a very large meal, participants consumed 40% more when given the larger serving, despite being unable to reliably identify which day they consumed more food. This result in the Samburu demonstrates the portion size effect is not a by-product of the modern food environment and may represent a more fundamental feature of human dietary psychology.

Original languageEnglish
Pages (from-to)212-216
Number of pages5
Early online date14 Nov 2018
Publication statusPublished - 1 Feb 2019

Structured keywords

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


  • Appetite control
  • Cross-cultural comparison
  • Externality
  • Food intake
  • Obesity
  • Overeating
  • Portion size effect


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  • NIHR BRC Nutrition

    Ness, A. R.


    Project: Research, Parent

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