To the best of our knowledge, the current study is the first study to investigate the interaction dietary patterns with the age of onset of obesity on body composition in Iranian women. Based on the principal components analysis, three main dietary patterns were extracted which included DASH, Unhealthy, and Western dietary pattern. In summary, this study evaluates the significant interaction between the DASH dietary pattern and the age of onset of obesity for BMI. The present study revealed that participants who followed the high intake DASH dietary pattern had lower BMI, visceral fat, and BFM compared to participants using the low intake pattern. We investigated a significant interaction between the unhealthy pattern with the age of onset of obesity on weight in the participants. Our study showed that subjects with an onset of obesity under 18 years who had the highest adherence to the unhealthy dietary pattern weighed less. The higher consumption western dietary pattern had no significant interaction with the age of onset of obesity in relation to body composition.
Among previous studies various dietary patterns and obesity were examined. A systematic review study investigated increased fruit and vegetable consumption and DASH dietary pattern and its association with reduced body weight, and their findings corresponded to the findings of the present study. The positive effect of the DASH dietary pattern on obesity in adolescence was reported(48). Sahar Golpour et al. observed that a high intake the DASH dietary pattern controlled hypertension and decrease risk obesity and overweight in children(49, 50). Another study revealed that adherence to the DASH dietary pattern in adolescents may decrease weight gain over a period of 10 years (51).The intervention study associated the low-fat dietary pattern with reduced BMI and fat mass, which is consistent with the results in the DASH pattern and change of body composition(52). A cross-sectional study examined the association between dietary patterns and body composition in participants. The study found a significant relationship between consumption of fruits and vegetables in adults that were associated with changes in body composition and BMI, while it found no association between the dietary patterns and central adiposity. Our results are in line with the results of this study on women. Nonetheless, the results of our study did not observe an interaction between the western pattern and age of onset of obesity for body composition(53).
Observational study has also suggested that the western pattern comprises red meat, processed meat, refined grains, sweets, desserts, French fries, and high-fat dairy products which increased obesity and hypertension(54). Based on the results of an research performed on 664 volunteers and its report published in 2009, a positive association was demonstrated between the western dietary pattern and anthropometric indices, obesity and plasma lipid concentration(55). Although the results of our study regarding the interaction between the western pattern and age of onset of obesity for body composition were not observed.
An association in 2014 was found between a dietary intake composing of fiber, bread, and fruits and vegetables with body composition. This dietary pattern decreased fat mass gain in girls, Also, the study observed mass gain in boys using packed lunches(56). Likewise the information of this study can be cited in our study.
The review article studied 18 articles indicating that the unhealthy dietary pattern using processed and red meats, mayonnaise, soft drinks, sweets, refined grains, snacks, fruit juice, nuts, French fries, eggs, butter, full-fat dairy products had a positive association with increase overweight and obesity ; thus, the results of our study were consistent with the results of the mentioned study(57). The principled mechanisms for the favorable interaction between the DASH dietary pattern and obesity and body composition are not completely understood. This dietary pattern which includes eating high quantities of fruits and vegetables and whole grains foods which have a rich source of fiber, potassium, magnesium, calcium, and phytochemicals may have utility effects on reducing obesity besides following DASH dietary pattern effect in satiety center in mind and lower glycemic index, in addition the mechanisms of DASH dietary pattern showed that consumption of fiber can effect on the secretion of insulin and glucagon reduced fat accumulation (58). The explanatory mechanism of the interaction effects of Unhealthy dietary pattern and obesity and anthropometric indicators suggests that the reverse effect of increasing intake high sugar content beverages, trans fat, saturated fat, high fat diary can be due to high levels of insulin secreted after eating a meal, leading to an increase in obesity related indices. In women who followed this dietary pattern, it was discovered that the diet lead to increased appetite and increased energy intake. These mechanisms described a direct negative effect on obesity(59).
Numerous articles have studied the relationship between dietary patterns and body composition, but no study has been done on the interaction of different dietary patterns and the age of onset of obesity on body composition. Our findings suggest a complex interaction of the three main dietary patterns and the age of onset of obesity for body composition in the overweight and obese woman in our study and offer insight into how dietary pattern interactions may increase the indicators that are associated with obesity.
The present study has some limitations that should be considered. First, the use of FFQs includes self-reporting of dietary intake for dietary assessment which can lead to biases in the reports of dietary intake, therefore it is suggested a more comprehensive questionnaire be employed for further research on the topic. Second, our participants consisted of only women. Thirdly, obese women were used in our study it cannot be representative of the general population. Fourthly, the study design was cross-sectional, which cannot provide information about the cause-and-effect relationship and lastly, a larger sample size population is required for further study.