British Journal of Nutrition

Full Papers

Human and Clinical Nutrition

Dietary changes in obese patients undergoing gastric bypass or lifestyle intervention: a clinical trial

Line K. Johnsona1a2 c1, Lene F. Andersena3, Dag Hofsøa1, Erlend T. Aasheima1a4, Kirsten B. Holvena3, Rune Sandbua1, Jo Røisliena1a5 and Jøran Hjelmesætha1

a1 Morbid Obesity Centre, Vestfold Hospital Trust, Box 2168, 3103 Tønsberg, Norway

a2 Norwegian Resource Centre for Women's Health, Oslo University Hospital Rikshospitalet, Oslo, Norway

a3 Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway

a4 Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK

a5 Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway


We compared changes in the dietary patterns of morbidly obese patients undergoing either laparoscopic gastric bypass surgery or a comprehensive lifestyle intervention programme. The present 1-year non-randomised controlled trial included fifty-four patients in the lifestyle group and seventy-two in the surgery group. Dietary intake was assessed by a validated FFQ. ANCOVA was used to adjust for between-group differences in sex, age, baseline BMI and baseline values of the dependent variables. Intakes of food groups and nutrients did not differ significantly between the intervention groups at baseline. At 1-year follow-up, the lifestyle group had a significantly higher daily intake of fruits and vegetables (561 (sd 198) v. 441 (sd 213) g, P= 0·002), whole grains (63 (sd 24) v. 49 (sd 16) g, P< 0·001) and fibre (28 (sd 6) v. 22 (sd 6) g, P< 0·001) than the surgery group and a lower percentage of total energy intake of saturated fat (12 (sd 3) v. 14 (sd 3) %, P< 0·001). The intake of red meat declined significantly within both groups, vegetables and fish intake were reduced significantly in the surgery group and added sugar was reduced significantly in the lifestyle group. The lifestyle patients improved their dietary patterns significantly (compared with the surgery group), increasing their intake of vegetables, whole grains and fibre and reducing their percentage intake of saturated fat (ANCOVA, all P< 0·001). In conclusion, lifestyle intervention was associated with more favourable dietary 1-year changes than gastric bypass surgery in morbidly obese patients, as measured by intake of vegetables, whole grains, fibre and saturated fat.

(Received May 28 2012)

(Revised August 09 2012)

(Accepted September 09 2012)

(Online publication October 30 2012)

Key Words:

  • Morbid obesity;
  • Gastric bypass;
  • Lifestyle intervention programmes;
  • Dietary intake patterns


c1 Corresponding author: L. K. Johnson, fax +47 33343991, email


  Abbreviations: FBDG, food-based dietary guidelines