From carbohydrates to fats? Long-term changes in dietary patterns in Portugal (1961–2023)

Background

Dietary patterns have changed substantially over recent decades, contributing to the rise of noncommunicable diseases. Within Popkin’s nutrition transition framework, many countries have shifted from traditional carbohydrate-based diets toward energy-dense patterns rich in fats, sugars, and animal-source foods. This study characterized the trajectory and stage of the nutritional transition in Portugal between 1961 and 2023.

Methods

Data were obtained from FAOSTAT food balance sheets. Food items were grouped according to the Portuguese Food Wheel, and daily availability (g/day/person) and energy contribution (kcal/day/person) were estimated. Macronutrient contributions were calculated and temporal trends analyzed using linear regression models.

Results

Total energy availability increased significantly (β = 14.86 kcal/day/person/year; p < 0.001). Macronutrient distribution shifted markedly: fat contribution rose (β = 0.273%/year; p < 0.001) while carbohydrates declined (β = −0.263%/year; p < 0.001), with a modest increase in protein (β = 0.052%/year; p < 0.001). The fat-to-carbohydrate ratio increased significantly, indicating progressive dietary energy densification. Food group trends showed declining availability of cereals, tubers, and legumes, alongside increases in animal-source foods, dairy products, fats, oils, and sugar products. Fruit and vegetable availability also increased. No statistically significant breakpoints were identified, suggesting a gradual transition.

Conclusions

Portugal has undergone a sustained nutritional transition consistent with Popkin’s Stage 4 (“degenerative disease” pattern), characterized by increased energy availability, a shift from carbohydrate-based staples toward fats and animal-source foods, and rising dietary energy density. These changes likely contribute to the burden of diet-related chronic diseases, highlighting the need for public health strategies promoting balanced, health-oriented, and sustainable dietary patterns.

Key messages

• Portugal shows a clear long-term shift from carbohydrates to fats, reflecting a progressive nutritional transition towards more energy-dense diets.

• Changes in food availability highlight increased consumption of animal products, fats and sugars, reinforcing the need for adequated nutrition policies.