A multicenter randomized controlled trial of a nutrition intervention program in a multiethnic adult population in the corporate setting reduces depression and anxiety and improves quality of life: the GEICO study

Am J Health Promot. 2015 Mar-Apr;29(4):245-54. doi: 10.4278/ajhp.130218-QUAN-72. Epub 2014 Feb 13.


Purpose: To determine whether a plant-based nutrition program in a multicenter, corporate setting improves depression, anxiety, and productivity.

Design: A quasi-experimental study examined the impact of diet on emotional well-being and productivity.

Setting: The study was conducted in 10 corporate sites of a major U.S. insurance company.

Subjects: There were 292 participants (79.8% women, 20.2% men), with body mass index ≥25 kg/m(2) and/or previous diagnosis of type 2 diabetes.

Intervention: Either weekly instruction in following a vegan diet or no instruction was given for 18 weeks.

Measures: Depression and anxiety were measured using the Short Form-36 questionnaire. Work productivity was measured using the Work Productivity and Activity Impairment questionnaire.

Analysis: Baseline characteristics were examined by t-test for continuous variables and χ(2) test for categorical variables. Analysis of covariance models were adjusted for baseline covariates. Paired t-tests were used to determine within-group changes and t-tests for between-group differences.

Results: In an intention-to-treat analysis, improvements in impairment because of health (p < .001), overall work impairment because of health (p = .02), non-work-related activity impairment because of health (p < .001), depression (p = .02), anxiety (p = .04), fatigue (p < .001), emotional well-being (p = .01), daily functioning because of physical health (p = .01), and general health (p = 0.02) in the intervention group were significantly greater than in the control group. Results were similar for study completers.

Conclusion: A dietary intervention improves depression, anxiety, and productivity in a multicenter, corporate setting.

Keywords: Depression; Health focus: nutrition; Manuscript format: research; Research purpose: intervention testing, program evaluation; Nutrition; Outcome measure: behavioral, productivity; Prevention Research; Productivity; Setting: workplace; Strategy: education, behavior change; Study design: quasi-experimental; Target population circumstances: education, geographic location, race/ethnicity; Target population: adults; Vegan; Vegetarian; Worksite.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anxiety / prevention & control*
  • Depression / prevention & control*
  • Diabetes Mellitus, Type 2
  • Diet*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Occupational Health*
  • Quality of Life*
  • Surveys and Questionnaires
  • United States
  • Workplace*