Effects of Portion Size on Energy Intake
Author Information
Author(s): Jeffery Robert W, Rydell Sarah, Dunn Caroline L, Harnack Lisa J, Levine Allen S, Pentel Paul R, Baxter Judith E, Walsh Ericka M
Primary Institution: University of Minnesota
Hypothesis
Chronic exposure to large portion sizes compared to small portion sizes would result in higher energy intake at meals, higher average total energy intake per day, and possibly an increase in body weight.
Conclusion
Chronic exposure to large portion size meals can result in sustained increases in energy intake and may contribute to body weight increases over time.
Supporting Evidence
- Mean energy intake at lunch was 332 kcal/day higher in large lunch than in small lunch periods.
- Mean 24-hour energy intake was 278 kcal/day higher in large versus small lunch periods.
- Average weight change was 0.64 kg during large lunches and 0.06 kg during small lunches.
Takeaway
If you eat bigger portions, you will likely eat more food and gain weight over time.
Methodology
Participants were given free box lunches of different portion sizes for two months, with dietary intake assessed through self-reports and 24-hour dietary recalls.
Potential Biases
Participants may have become aware of the portion size manipulation during the study.
Limitations
The study had a small sample size and limited duration, which may affect the generalizability of the findings.
Participant Demographics
Participants were women aged 18 to 40, with a mean age of 33 years, 45% married, 65% with at least a 4-year college degree, and 80% white.
Statistical Information
P-Value
p < 0.0001
Statistical Significance
p < 0.001
Digital Object Identifier (DOI)
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