INTRODUCTION

Physical inactivity and sedentary behavior are modifiable factors associated with diseases of public health significance, namely diabetes, cardiovascular diseases, cancer, and metabolic syndrome, among others¹. Worldwide, 27.5% of adults are physically inactive², while in Mexico the 2018 National Health and Nutrition Survey (ENSANUT, per its Spanish acronym) reported that 17.3% of adults were insufficiently active that is, adults practiced <150 minutes of moderate or vigorous activity per week and women followed the recommendations to a lesser extent³. Likewise, sedentary behavior refers to all those wakefulness activities such as, sitting, lying down and use of screens for entertainment purposes with minimum energy expenditure (≤1.5 MET). In Mexico, using a cut-off point of > 7 hours per day, sedentary behavior is estimated to be 11.3%⁴.

On the other hand, it has been observed that in young adult populations the most active people tend to maintain healthier diets⁵. However, there are some contradictory results that may be influenced by methodological aspects⁶. In this sense, Mexico is undergoing a nutritional transition that has changed dietary patterns (DPs). Some factors, such as globalization and industrialization, have allowed processed, ultra-processed and energy-dense foods to be incorporated into the traditional diet, which in turn has led to a decrease in the consumption of fresh and minimally processed foods rich in vitamins, minerals and fiber⁷. These changes are viewed in the high consumption of discretionary foods, namely sugary, non-dairy drinks (86.7%), sugary cereals (35.9%) and snacks, sweets and desserts (29.8%)⁸. The university phase is a period of interest, since students undergo a complex change process and are exposed to a set of unique factors that determine dietary intake⁹, namely increased autonomy, high study load, and high levels of stress, anxiety, low physical activity, skipping meals, nibbling, fast foods and extreme diets due to weight concerns, among others¹⁰. The association between DPs, physical activity and sedentary lifestyle is much clearer in children and adolescents¹¹, but not in adults¹². In addition, in Mexico there is limited evidence on these associations in university students¹³. In this sense there is evidence where dietary patterns have been identified in university students as “healthy”, “traditional-westernized” and “animal protein and alcohol drinks”, with a healthy pattern being associated with a higher level of physical activity¹³. On the other hand, in a nationally representative sample of adults, individuals with a traditional pattern reported a higher level of physical activity¹⁴.

It is important to mention that the study population is characterized by a high degree of poverty and a higher proportion of the country's indigenous population, which preserves its cultural identity, factors that can influence food and physical activity.

On this basis, this study aimed to identify DPs and their association with physical activity and sedentary behavior among university students from Southwest Mexico.

MATERIALS AND METHODS

RESULTS

Of the total sample 54.2% were women, 50.3% were in the 17-20 age range, and 14.3% of the sample was characterized as indigenous. Regarding academics, 42% were from the health sciences, followed by management (34.1%) and engineering (23.9%). With regard to physical activity, 49.9% was classified as moderate, followed by high and low (25.8% and 24.3%, respectively). Regarding sedentarism, 85.7% reported sitting for six or more hours, while the rest indicated less than six hours (14.3 %) (Table 2).

The average consumption of the thirteen food groups was used for the pattern analysis considering the previously indicated criteria. Three DPs were identified, which together explained 33% of the total variance. The “traditional” pattern explained 13.19% of variance and was characterized by the consumption of vegetables, fruits, white meat and traditional food. The “western” pattern explained 10.69% of the variance and was identified by the consumption of red meat, dairy products, and fast food. The “prudent” pattern explained 10.03% of the variance and was differentiated by the consumption of vegetables, white meat, eggs and cereals (Table 3).

Students in the highest quintile of adherence to the traditional pattern were categorized in their highest proportion (p<0.001) in the area of health sciences (30.8%), had higher physical activity (33.3%) and energy consumption was lower than in the other quintiles (p= 0.005 and p= 0.009, respectively) (Table 4). Participants in the highest quintile of adherence to the western pattern were more frequently categorized (24.5%) in the academic area of health sciences (p= 0.031).

Regarding energy consumption, the highest quintile of adherence to the prudent pattern had a lower energy consumption (p<0.001) (Table 4).

After adjustment by, DPs, age, sex, indigenous identify and academic area, greater adherence to the traditional pattern was positively associated with high physical activity (OR:2.78; 95% CI: 1.34-5.75); while for sedentarism a negative association was found (OR:0.35; 95% CI: 0.13-0.93) (Table 5).

DISCUSSION

This study aimed to analyze DPs among university students from the Isthmus of Tehuantepec, located in Oaxaca, Mexico, and their associations with physical activity and sedentary behavior. Three DPs were identified: “western”, “prudent” and “traditional”. Regarding physical activity, women were less active compared to men. Furthermore, a positive association of “traditional” pattern with high physical activity and less sedentary behavior was found.

The western pattern, characterized by the consumption of red meat, dairy products, and fast food (hamburgers, pizza, hot-dogs), has been described in another study in Mexico²⁰. This type of pattern has been associated with developing overweight and obesity, insulin resistance, high levels of LDL cholesterol, coronary heart disease, type 2 diabetes mellitus, and hypertension^6,20,21. Therefore, the presence of this pattern in the population university is a concern because of the possible metabolic implications in the future.

In this study, the prudent pattern, which was characterized by the consumption of vegetables, white meat, eggs and cereals and less consumption of typical foods, is similar to that reported by Denova et al. in Mexican adults, which is characterized by the consumption of vegetables, fruit and cereals [18], and by another study in Mexico²². This pattern has been reported as healthy²³ and negatively associated with metabolic problems and lower cardiovascular risk¹⁸. This is expected, since including food groups, such as fruits, vegetables and whole grains, increases the consumption of vitamins, minerals, phytochemicals and fiber²⁴, which benefit health.

The traditional pattern characterized by the consumption of fruits, vegetables, dairy products and traditional food (garnachas, tlayuda, pollo garnachero, tostadas and totopos), has been described in other investigations in Mexico. Flores et al. reported a traditional pattern mainly characterized by the consumption of tortillas and legumes¹⁴. Corn tortillas are a food usually present in the different traditional DPs reported in Mexico. However, in the study population, the corn tortilla is usually replaced by the consumption of other corn-based foods typical of the Isthmus of Tehuantepec, namely totopos, which may be baked or fried. While it is true that naming pattern derives from a series of subjective decisions²⁵ and may vary due to the availability of certain typical foods in each region, it has been reported that the different variations describing the traditional Mexican pattern have been considered healthy. This information has been confirmed by a recent systematic review²⁶. Although the basis of typical or traditional foods are considered healthy, some of these foods are fried, which could reduce their nutritional quality. However, the factor loadings of fruits, vegetables and white meat were higher than those of traditional food together with low consumption of sugar and pastries, which is why the traditional pattern in this study can still be considered healthy.

Some authors have reported a traditional-Westernized dietary pattern, as traditional foods and foods typically included in the Western diet, such as fast food²⁷, merge into one dietary pattern. Betancourt et al. reported a traditional-Westernized dietary pattern characterized by the consumption of traditional Mexican foods, namely tubers, legumes, native cereals, animal fats and milk, as well as Western foods such as pastries, sugars, refined cereals, fast foods and sugar-sweetened beverages¹³. In other studies, this DP is reported as transitional²³. This type of DP has been attributed to the nutritional transition exacerbated by the inclusion of processed foods into the traditional diets of various countries. In Mexico, the international agreements, like the United States-Mexico-Canada Agreement (USMCA) that substituted the previous free-trade agreement of North America (NAFTA) have facilitated the entry of several food industries and have increased the availability of ultra-processed foods⁷. High energy food and foods rich in sugar, sodium, fat and very low in fiber have been added to the traditional diet. It is noteworthy that Oaxaca is one of the states located in the less developed regions of the country, preserves a greater cultural identity and has a larger indigenous population, which could explain the presence of the traditional pattern. On the other hand, the extent of poverty, urbanization and level of schooling may explain the tendency to consume high-energy foods, as they are cheaper in a transition towards a Western pattern, as previously reported²⁸. However, there are other sociodemographic and cultural variables that must be explored in future studies to show how these factors may influence DPs.

Although the effect of physical activity and dietary habits on the presence or absence of diseases has been established, the capability of these two behaviors to indirectly modify each other has been poorly documented²⁹. Some studies have reported an association of high physical activity with healthier DPs that include fruits, vegetables, whole grains, and other foods that benefit health³⁰. On the other hand, low physical activity has been associated with less healthy patterns related to adverse health effects³¹. It has been proposed that physical activity may act as a reward ‘buffer’ against liking and craving for high-fat foods, while low physical activity levels may lead people to adhere to hedonic hunger³². The impact of physical activity on food reward is difficult to assess due to the lack of randomized controlled trials and differences between study designs³³. However, some studies have reported that the most active people, either men or women, tend to consume less fat compared to those who are sedentary or inactive, and they also consume a greater amount of fiber and tend to consume healthier foods^34,35. One of the few prospective studies reported that people who increased their physical activity also reported an improvement in diet quality³⁶. On this basis, an association between high physical activity with the prudent pattern was expected to be found, as documented³⁷. However, such association was not observed in our study. Instead, it was noted that the most active students adhered to the consumption of a traditional pattern, which has been considered healthy²⁶. Thus, the association between the traditional pattern and high physical activity in the study population would not be a coincidence, as it is in line with another study carried out in Mexico²⁴. Another recent study concluded that a 12-week physical exercise intervention reduced consumption of high-reward foods³⁸, which might strengthen the hypothesis that the consumption of the healthiest food, might be motivated by high physical activity or that behavioral changes can go hand-in-hand.

Furthermore, our results revealed a high proportion of sedentary students, which is a concern, as sedentary behavior has been reported to be associated with both a lower consumption of healthy foods³⁹ and, generally, unhealthy dietary habits. Therefore, the occurrence of chronic non-communicable diseases may be conditioned by these aspects. In this sense, an association of the western pattern with low physical activity and sedentary behavior was expected to be found, as reported in Mexico²⁰. However, there was no such association. This could be explained because in our study sedentary behavior was generally assessed by considering the total hours per day that participants spent in a sitting position. Nonetheless, there are no defined cut-off points for sedentary behavior, since the variability of waking hours is influenced by the context of each country. Also, different sedentary behaviors were not studied in depth, which may be associated with a less healthy pattern. However, it was observed that, according to the cut-off point considered for our study, the traditional pattern was associated as a protective factor against sedentary behavior, which is in line with other studies reporting that healthier patterns are inversely associated with sedentary behaviors⁴⁰.

This study has some limitations. One of them is the study design, since causality cannot be inferred. Thus, it is not completely clear whether physical activity induces a change in diet or vice versa. However, as mentioned above, studies in this field tend to suggest the influence of physical activity on food consumption. Another limitation was the relatively low frequency of foods, which led to a reduced number of food groups. Nonetheless, it is important to point out that it is our understanding that this is the first study dealing with analysis of DPs through principal components and their associations with physical activity and sedentary behavior in the study region, which lay the foundations for further research.

CONCLUSIONS

Among university students we identified the following eating patterns: “traditional”, “western” and “prudent”, considering the first and the third as healthy. In adjusted analysis, we observed that greater adherence to the traditional pattern was associated with higher physical activity and less sedentarism.

The results are inconclusive and more evidence is needed to demonstrate the relationship between high physical activity, sedentarism and eating. Future studies may consider designing interventions focused on improving diet quality, increasing physical activity and decreasing sedentary behavior, through multidisciplinary programs to encourage healthy behaviors in the university population.