Adherence to dietary guidelines for the Spanish population and risk of overweight/obesity in the SUN cohort

Abstract

Dietary guidelines play a key role in setting standards for nutrition policies and promoting healthy eating. Like other public health guidelines, they are often influenced by political and economic factors that could place other concerns ahead of the population's health. In order to determine their effectiveness on obesity prevention, we prospectively examined the association between adherence to the latest available national dietary guidelines and the incidence of overweight/obesity in a Spanish cohort study. A sample of 11,554 participants of the "Seguimiento Universidad de Navarra" (SUN) cohort, initially free of overweight or obesity, was included in the study. The Spanish Society of Community Nutrition (SENC) food pyramid (FP) score was computed based on the ratio of consumed to recommended daily servings of grains, fruits, vegetables, dairy, protein-rich foods, olive oil, red and processed meat, sweets, salty snacks and spreadable fats, fermented alcoholic beverages and water. The same approach was followed to calculate the SENC hydration pyramid (HP) score, considering the intake of water and different kind of beverages. Adherence was calculated at baseline and after 10 years of follow-up. Cox proportional hazards models were used to assess the incidence of overweight/obesity (BMI ≥25 kg/m2). During a median follow-up of 10.3 years, 2320 incident cases were identified. The highest level of adherence to the SENC FP score was modestly associated with a reduced risk of overweight/obesity (multivariable-adjusted HR for the fifth quintile vs. the first quintile = 0.78; 95% CI: 0.67-0.91; p-trend: 0.007). No consistent trends were found for the SENC HP. In a large prospective cohort of Spanish university graduates, we found an inverse linear association between adherence to the SENC FP and overweight/obesity risk, whereas this was not the case for the HP.

Fig 1. Flow chart of the selection process among participants of the SUN cohort.

Fig 2. Generalized estimating equation model with average BMI (kg/m², continuous) as the outcome during 16 y of follow-up according to extreme and median quintiles of the SENC (Spanish Society of Community Nutrition) Food Pyramid score.

Multivariable model adjusted for sex, age, baseline BMI, physical activity, hours of TV watching, energy intake, smoking, marital status, level of education, sleeping siesta, snacking between meals, following a special diet, family history of obesity and year of recruitment.

Fig 3. Restricted cubic splines of the association between the SENC (Spanish Society of Community Nutrition) Food Pyramid score and risk of overweight/obesity in the SUN cohort.

Multivariable model adjusted for sex, age, baseline BMI, physical activity, hours of TV watching, smoking status, marital status, highest level of education achieved, total energy intake, snacking between meals, following a special diet at baseline, family history of obesity and hours of siesta. Age was used as the underlying time variable and model was stratified by age groups and year of recruitment.

Fig 4. Multivariable-adjusted HRs for overweight/obesity according to adherence to the SENC Food Pyramid score (above vs. below the median [P50]) with different quantitative definitions for occasional food and alcohol consumption.

The SENC FP does not provide quantitative guidance for food groups limited to an occasional consumption (red and processed meats, sweets, salty snacks and spreadable fats). We defined occasional consumption as <1 serving/day in our main analyses based on previous research. The SENC FP also includes the possibility of a moderate consumption of fermented alcoholic beverages (defined as 1–2 servings/day according to sex). Alternatively, we assessed the effect of the SENC FP on overweight/obesity risk defining occasional consumption as <2 servings/week and excluding the possibility of consuming alcohol.