Objective: To determine in a representative Dutch sample the association of dietary restraint, Concern for Dieting, and Weight Fluctuation with subsequent change in body mass index (BMI; in kg/m2) in addition to possible moderator effects of sex, level of education, age category, ethnicity, overweight level and physical activity. Design: In a longitudinal study in a representative Dutch sample consisting of 675 participants (331 females, 344 males), dietary restraint (including Concern for Dieting and Weight Fluctuation) was assessed with the Restraint Scale at baseline, and also self-reported weight and height. Three years later, weight and height were also assessed. Results: Dietary restraint was significantly associated with an increase in BMI after three years (B = .272, p = 001). Inspection of the significant moderator effect of sex (B = −.387, p = .012) indicated that dietary restraint was significantly associated with increases in BMI only in females. There was no main effect for Concern for Dieting (p = .091). There was a moderator effect of sex on the association between Concern for Dieting and BMI change (B = −.424; p = .002): initial concern for dieting was positively associated with subsequent body mass gain only in women. Weight Fluctuation was significantly associated with an increase in BMI after three years (B = .162, p = 008) and sex did not moderate this association. There were no moderator effects for level of education, age category, ethnicity, overweight level and physical activity. Conclusion: Dietary restraint and Concern for Dieting are associated with increases in BMI only in females. Weight Fluctuation is associated with increases in BMI in both males and females.
Does dietary restraint, the attempted restriction of food intake to control body weight, suppress or promote future weight gain? The few longitudinal studies in the general population show contradictory results. In the 2-year follow-up study by de Lauzon-Guillain et al. (2006), initial dietary restraint did not predict subsequent weight change. In contrast, in the 6-year follow-up study by Chaput et al. (2009), those with high initial dietary restraint scores were significantly more likely to subsequently gain weight and become obese.
The association between dietary restraint and subsequent weight change may be moderated by sex. In the 6-year follow up study by Drapeau et al. (2003), initial dietary restraint was positively associated with subsequent weight gain in women but in men the association was negative. Similarly, in the 1-year follow-up study by Klesges, Isbell, and Klesges (1992), dietary restraint was associated with weight gain in women but not in men.
Possible moderator effects of level of education, age category, ethnicity, degree of overweight and physical activity on the relationship between baseline dietary restraint and change in BMI have not yet been examined, and none of the studies have been conducted in a representative sample. Accordingly, in a 3-year follow-up study in a representative Dutch sample we examined the moderator effects of these factors and sex in addition to the main effect of dietary restraint on BMI change. As the measure of dietary restraint, we used the Restraint Scale (RS) Herman, Polivy, Pliner, Threlkeld, & Munic, 1978, because this scale permits analyses of the independent contribution of Concern for Dieting and Weight Fluctuation, two sub-scales of the Restraint Scale. One may also examine the contribution of dietary restraint or Concern for Dieting with and without the Tendency toward Disinhibition (the RS item: I eat sensibly in front of others but splurge alone) ( Van Strien, Breteler, & Ouwens, 2002). Finally, the RS permits assessment of possible effects of frequency of dieting (The RS item: I diet).
