Ultra-processed food consumption and obesity-a systematic review

Background and objectives: a number of studies suggest a relationship between the intake of ultra-processed foods and the prevalence of obesity. Specifically, this type of food provides large amounts of free sugars and saturated fats, which contribute to a high energy intake. In the last few decades, consumption of these products has increased to the point of representing an important amount of calories in the daily diet of several populations. As a result, foods that are usually consumed in healthy eating patterns containing fiber, complex carbohydrates and fats are displaced. This systematic review aimed to compile the information in the literature, and to examine the scientific evidence about the relationship between ultra-processed food and obesity. Material and methods: a systematic review was performed of the PubMed database. PRISMA criteria were applied to identify those papers published from 2000 to April 2020 that met the following criteria: original articles (in English or Spanish), dealing with research in human subjects, with exclusion of pregnant women. The search was performed using the terms "ultra-processed food and obesity" and "ultra-processed food and overweight", which resulted in a total of 12 references: 7 cross-sectional studies, 3 prospective cohort studies, and 2 ecological studies. Results: a positive association was found between ultra-processed food consumption and obesity in 9 of the 12 papers included in the review. However, limitations exist regarding the heterogeneity of methodologies or use of different food classification systems according to processing degree. Conclusion: further studies are needed to establish the relationship between ultra-processed food consumption and the prevalence and incidence of obesity.