Objective: To examine the weight-loss success associated with distinct dietary patterns and to determine changes of these dietary patterns during participation in a web-based weight-reduction programme. Design: Factor analysis was used to identify the dietary patterns of twenty-two food groups that were administered in 14 d dietary protocols at baseline and after 3 months. Successful weight loss (≥5 % of initial weight) and BMI were calculated. Logistic regression analyses were used to assess the rates of weight-loss success from each dietary pattern and changing or remaining in the initial dietary pattern. A generalised linear mixed model was used to estimate the effects of changing or staying in a dietary pattern on change in BMI. Subjects: Adults (n 1635) aged 18-81 years. Setting: Users of a web-based weight-reduction programme (2006)(2007)(2008)(2009)(2010)(2011)(2012). Results: Participants who aligned to a healthful dietary pattern at baseline (OR = 1·8; 95 % CI 1·5, 2·3) and after 3 months (OR = 1·5; 95 % CI 1·2, 1·9) had a greater chance of successfully losing weight. After adjusting for age, sex, initial dietary pattern and BMI, participants who started with or changed to the healthful dietary pattern had a greater chance of being successful (OR = 1·4; 95 % CI 1·1, 1·7) and a higher BMI reduction of 0·30 (95 % CI 0·2, 0·5) kg/m 2 compared with those who started with or changed to the energy-dense or high-carbohydrate dietary pattern. Conclusions: A favourable healthful dietary pattern at the beginning and after 3 months was positively associated with anthropometry. However, successful weight loss was feasible in each dietary pattern.
Key words Dietary patternsWeight loss Factor analysis Online weight-reduction programme In Europe, more than 50 % of men and women are overweight (1) . A BMI above 30 kg/m 2 is present in 21 % of women and 22 % of men aged 20 years or older (2) . Moreover, worldwide, the prevalence of obesity has almost doubled between 1980 and 2008 (1) . Obesity is an important health risk for diseases such as diabetes mellitus type 2, hypertension, CVD and others (3) . Nevertheless, weight is adjustable, and a moderate weight reduction of 5-10 % is associated with enhanced health benefits (4) . Weight gain is the result of an imbalance between energy intake and expenditure; however, the effect of different dietary factors on weight gain or weight loss remains unclear (5)