Ultra-processed foods drive obesity and metabolic risks

Find out how ultra-processed foods fuel obesity and metabolic risks, and why embracing a Mediterranean diet could turn the tide on rising health problems.

Study: A close relationship between ultra-processed foods and adipose tissue in adults in southern Italy. Image credits: Rimma Bondarenko / Shutterstock

This is evident from a recent study published in the journal Nutrientsa group of researchers in Italy examined the relationship between consumption of ultra-processed foods (UPFs), obesity, and adiposity measures among adults in southern Italy.

Background

Obesity is a global public health problem, with food processing playing a key role in its rise. Modern food systems have shifted diets toward energy-dense UPFs, which are highly palatable, nutrient-poor, and calorie-dense. UPFs, identified by the NOVA classification, include snacks, soft drinks and processed meats that are linked to increased obesity rates. Although studies suggest a strong link between UPF consumption and obesity, the limitations of observational studies, including reliance on research instruments not designed to assess food processing, necessitate further research. These studies are often based on simplistic measures such as body mass index (BMI), highlighting the need for more robust methods to better understand their impact on health.

About the study

The present study was conducted in the outpatient clinic of the IP “Diet Therapy in Transplantation, Renal Failure, and Chronic Pathology”, University of Naples Federico II. Data were collected from 175 participants aged 18-65 years with a BMI ≥30 kg/m², recruited between October and December 2021. Participants were stratified into three BMI-based groups: Class I obesity (BMI 30- 34.9 kg/m²), Class II obesity (BMI 35-39.9 kg/m²) and class III obesity (BMI ≥40 kg/m²). Exclusion criteria included bedridden status, pregnancy, cancer, dementia, depression, breastfeeding, diabetes, or neurological disorders.

Anthropometric measurements, including weight, height, and waist circumference, were collected according to standardized protocols. Body composition was assessed using bioelectrical impedance analysis, and subjects adhered to pre-measurement conditions, including fasting and avoidance of caffeine or physical activity. In addition, biochemical parameters such as triglycerides, HDL cholesterol and the triglyceride-to-HDL ratio were evaluated as markers of insulin resistance. Blood pressure was measured according to the European Society of Cardiology (ESC) guidelines.

Nutritional assessments used the PREvención con DIEtaMEDiterránea (PREDIMED) and NOVA Food Frequency Questionnaires (NFFQ) to evaluate adherence to the Mediterranean diet and UPF consumption. Adipose tissue was analyzed using indices such as waist-to-height ratio (WHtR), lipid accumulation product (LAP), visceral adipose tissue index (VAI) and cardiometabolic index (CMI). Statistical analysis was performed using SPSS, with significance set at p < 0.05.

Study results

A total of 175 participants, 36% of whom were male, with a mean age of 43.3 ± 12.6 years and a BMI of 42 (95% CI: 37-47), were analyzed to assess eating habits in relation to BMI. to assess. Most participants were married and had attended high school, with no statistically significant differences in sociodemographic characteristics, physical activity, or education level between BMI groups. However, individuals with higher BMI values ​​were more likely to live in small to medium-sized cities than those in the lowest BMI group, who lived mainly in metropolitan areas (p < 0.05).

UPF consumption increased significantly with BMI, both in percentage and absolute terms. In Group 1, UPF consumption accounted for 18.2% (95% CI: 16.7-23.5), compared to 26.2% (95% CI: 26.6-32.5) in Group 3 (p < 0.01). Daily UPF intake increased from 274.2 g/day (95% CI: 241.5-495.5) in Group 1 to 526.2 g/day (95% CI: 575.9-802.8) in Group 3 (p < 0.001). Soft drinks made the largest contribution, with consumption more than doubling in Group 3 compared to Group 1 (p < 0.01). Higher BMI groups also showed increased consumption of sweets and chips, sausages, savory snacks, ice cream and nuggets (p < 0.05 to p < 0.001), while consumption of MPFs decreased significantly as BMI increased (p < 0.001) .

Adherence to the Mediterranean diet (MD) was poor in all BMI groups, with a significant decrease observed as BMI increased. Group 3 participants had a PREDIMED score of 5 (95% CI: 4.8-5.3), reflecting lower MD therapy compared to groups 1 and 2 (p < 0.005).

Further analysis divided participants into tertiles based on UPF consumption, revealing a significant trend of younger participants in the highest UPF tertile (p < 0.05). Higher UPF consumption was associated with increased lipid indices including WHtR, VAI, LAP, CMI and Waist Triglyceride Index (WTI) (p < 0.001). WHtR increased from 0.6 (95% CI: 0.6-0.7) in T1 to 0.7 (95% CI: 0.7-0.8) in T3. VAI and LAP values ​​increased significantly, with the latter increasing from 80.4 (95% CI: 65.9-91.4) in T1 to 113.6 (95% CI: 95.3-129) in T3 . These findings highlight a clear association between higher UPF consumption and adverse adipose tissue-related outcomes.

Conclusions

In summary, this study shows a positive association between UPF consumption and obesity, with increased UPF intake linked to higher body fat indexes and decreased adherence to the MD. Soft drinks were the biggest contributor, with consumption increasing along with BMI, followed by processed snacks and ready-made meals. The hyper-palatable taste, high energy density, and additives in UPFs can promote overeating, visceral fat accumulation, and metabolic disorders. Furthermore, the study highlights the higher cardiometabolic risks observed in participants with elevated WHtR and VAI indices. Increased indices such as WHtR and VAI in consumers with a high UPF indicate an increased cardiometabolic risk.

The authors point out limitations, including the retrospective nature of the study and the lack of assessment of stress levels and sleep quality, which may influence adipose tissue outcomes. These findings underscore the need for public health strategies to promote traditional diets such as the Mediterranean diet and limit UPF intake as part of obesity prevention efforts.