Obesity is a major health concern in children and adolescents. The prevalence of obesity among children and adolescents remains high level and an upward trend (1). From 1975 to 2016, the global prevalence of obesity and overweight increased around eight-fold (from 0.7 to 5.6% in girls and from 0.9 to 7.8% in boys) in children aged 5–19 years (2). The estimated global prevalence of overweight and obesity increase from 10 to 20% in boys and from 14 and 24% in girls, hinting that around 400 million children and adolescents may be suffered by 2035 (3). According to the survey, the obesity prevalence rate among preschool children in Jiangsu is 14.0% (4). Alarmingly, the overall prevalence of overweight and obesity among children aged 6–17 years old has soared to 38.60% (5), highlighting a concerning trend in childhood weight management in the region.

The first 1,000 days of life is essential to individual’s development, and would influence the health of adults and aging duration (6). Early life factors contributing to obesity in children include adverse health conditions during pregnancy, unhealthy feeding methods, and environmental risk factor exposures (7). Breastfeeding was considered an effective feeding pattern to prevent obesity and a significant protective factor of obesity (8, 9). Compared with formula-fed children, breastfed children commonly accompanied by a lower incidence of obesity (9). Some studies have found a dose–response protective relationship between the duration of breastfeeding and the risk of overweight/obesity (10, 11). Compared with child accepted breastfeeding for 2 months, those undergone breastfeeding for 5 months showed higher lean mass, skeletal muscle mass and lower total body fat mass. Besides, for the girls, a positive linear relation between breastfeeding duration and trunk lean mass was demonstrated (12).

Sourced from various databases, 28 guidelines, either globally recognized or developed globally by governments, professional organizations, or expert groups, focused on obesity management for children and adolescents with obesity-related comorbidities or severe obesity. They recommended weight loss as the primary treatment method, with only 10 guidelines specifically emphasizing dietary management (13). Childhood is a critical period for the formation of dietary patterns and habits; reasonable guidelines of dietary management are needed for the children with overweight or obesity. Moreover, given the discrepant metabolism status between children and adults, the recommended dietary intervention protocols for adults’ body weight management are not usually suitable for children (14), thus evidence-based specific and efficient clinical body weight management protocol is expected for controlling children obesity. Data from some clinical interventions have demonstrated the impact of change in lifestyle on children obesity or overweight (15). Compared with the control group, 16-week lifestyle intervention (include nutritional counseling and physical exercise) could significantly reduce the BMI z score and percentage body fat in obesity child (16).

To date, few studies have explored the linkage of early life diet (represented by breastfeeding duration and dietary habits after weaning) and lifestyle with body weight and obesity, as well as their combined effect on the risk of obesity in child. Therefore, a cross-sectional study was designed to explore the relation between breastfeeding duration and lifestyle with childhood obesity. The data from our study will provide reference for formulating early life feeding method and lifestyle-based preventive and interventional strategy of obesity in children and adolescents.

In this cross-sectional study, we found that early breastfeeding and health dietary habits during childhood are protective factors for childhood obesity.

Multiple studies have shown that, in comparison with artificial feeding, breastfeeding is an efficient feeding method for preventing childhood obesity (24, 25). However, some researchers reported that there was no significant correlation between breastfeeding and obesity (26). In our study, we observed that children who received 4–12 months breastfeeding displayed a significantly lower risk of obesity comparing with those who accepted breastfeeding for less than 4 months, although there was no significant difference in the duration of breastfeeding between children with and without obesity. The conclusions regarding the impact of prolonged breastfeeding duration on childhood obesity or overweight were controversial. Data from Liese’s study found that breastfeeding for more than 1 year significantly reduced the risk of childhood obesity in a dose–response relationship (12). In contrast, others’ results demonstrated that, comparing with the children underwent breastfeeding for 6–9 months, the children accept breastfeeding more than 2 years have decreased risk of obesity and overweight by about 45% (49), but not difference on the risk of obesity as comparing with the child received 1–2 years breastfeeding (11). The World Health Organization recommended the gradual addition of complementary foods to 6-month-old children (27), which could be a potential modifier on the relation between breastfeeding and obesity in children. Therefore, it is necessary to take the addition of complementary foods into the consideration when analyzing the impact of breastfeeding duration on chronic diseases in child.

With the rapid economic development and urbanization progress in China, the incidence of stunted growth and thinness among Chinese children has decreased dramatically (28). Meanwhile, childhood obesity has become a priority public health concern in China. Study has indicated that westernized diet and the change of dietary pattern were major reasons for increased childhood obesity prevalence (29). The living environment of children, such as family and school, is another environmental risk factor that affects childhood obesity (30, 31). For individuals, excessive nutrient intake or unhealthy lifestyle and dietary habits are the most direct risk factors for childhood obesity (32). In this study, we found differences in dietary habits between children with and without obesity, such as preference for meat-based foods, heavy or popular flavor, and habit of snacking before meals.

The relationship between meat intake and obesity is controversial. In a study of Iranian children, the intakes of white meat and poultry were associated with increased risk of general obesity, while the consumption of processed meat was associated with central obesity (33). In a study conducted in China, researchers found a positive association between red meat consumption and overweight and obesity in girls (34). For children and adolescents, the proportion of overweight and obese without weekly meat intake was higher than the proportion of children with daily meat intake (12.3% vs. 11.1%) (35). Data from prospective research confirmed the preventive effect of plant-derived diet on obesity, and the transition from animal-derived foods to plant-derived foods was also recommended to prevent chronic diseases and promote health (36). Patients with obesity commonly prefer “salt, umami, and fatty” foods (37). Consistently, in our study, the children with obesity also self-reported a preference for heavy flavored foods. Additionally, studies have found that children who are breastfed for longer durations develop a preference for neutral flavored foods with less sweetness and fat (38). These results demonstrated that breastfeeding-based dietary favor might partially explain the preventive role of breastfeeding on childhood obesity. Moreover, nowadays, because of habitual fried snacks intakes, children’s intake of high-fat and salty foods has increased correspondingly (39). Especially, the consumption of snacks before stable meals further increased satiety of the child, resulting in reduced sense of hunger and desire for foods, and therefore disturbing the normal consumption of stable meals (40).

Interestingly, in the current study, we also found that the children with obesity consumed more types of food per day in comparison with the non-obesity ones. The dietary diversity score is an indicator constructed to evaluate individual’s dietary habits based on the types of foods consumed. Researchers have found a negative correlation between obesity and the Dietary Diversity Score (DDS) in children, and an increased DDS suggests a reduced risk of overweight (41). Results from another study also revealed that the dietary diversity was positively correlated with overweight in male Chinese (42), and the same relation was observed in the study conducted in preschool children in the United States (43). Discrepant impacts of plant-derived and animal-derived foods on the risk of obesity may be the reason for explaining the different correlations between dietary diversity and childhood obesity. An in-depth investigation is expected to further explore the relation between plant derived DDS and animal derived DDS with childhood obesity in future research. The dietary management for childhood obesity should focus on controlling total daily energy intake, adjusting food proportion, and choosing appropriate food types, rather than simply limiting food intakes. Replacing foods that potentially increased the risk of obesity, including processed foods, snacks, red meat, and refined grains (44) with more light meat, fish, vegetables, and whole grains, might be a smart way to guarantee food diversity, and effectively preventing childhood obesity.

Evidence has shown that combination of dietary intervention with physical activity or psychology treatment could efficiently control body weight (45). In our study, physical activity was a significant factor contributing to the risk of childhood obesity. Overweight adolescents with less daily physical activity habit are susceptible of becoming obese after grow up in the future (46), so adequate physical activity was commonly recommended to the overweight adolescents to prevent obesity in adulthood. Unfortunately, most primary and middle schools could not implement the sports activity guidelines (47), thus, there is still a long way to go for the schools, communities, clinics, and the government to fulfill the physical activity interventional policies (48), to reduce the incidence of childhood obesity and obesity related chronic diseases.

The major innovation of this study is the comprehensive analysis of early life diets (exclusive breastfeeding) and lifestyles (dietary habits and physical activity) with childhood obesity. However, there are still some limitations. Firstly, this study only investigated the duration of breastfeeding without clarifying whether complementary foods have been added and the time for adding complementary foods was unknown, which may be a potential confounding factor of the study. Dietary habits were influenced by the socioeconomic status of family/parents, but the study lacks investigation. Therefore, a more detailed survey needs to be developed in future research. Secondly, the cross-sectional study design made us fail to analyze the time trajectory changes of obesity in child underwent different breastfeeding duration and lifestyle habits, therefore could not determine the contribution of dietary pattern adjustment and food choices to the incidence of childhood obesity. Moreover, the study did not separately explore how breastfeeding duration and lifestyle factors affect obesity differently in males and females, which requires further analysis in the future. Finally, the small sample size was a major limitation of this study, and large scale prospective or randomized controlled trials are needed to provide more reliable and precise scientific evidence.

In this study, we found that: (1) the dietary habits of children with obesity manifested as consuming more meat-based foods, preferring heavier flavor, and frequently snacking before meals; (2) breastfeeding for 4–12 months significantly reduced the risk of childhood obesity; (3) healthy lifestyle habits and prolonged breastfeeding duration are both protective factors for childhood obesity respectively, and the synergistic impact of healthy lifestyle habits and prolonged breastfeeding on the prevention of childhood obesity is much more significant.