The definition of diet quality varies depending on dietary habits, cultural background, the availability of local foods, and individual requirements (such as age, gender, and level of physical activity). However, it can be stated as the adequacy of essential nutrients and energy in supporting bodily functions, promoting well-being, facilitating physical activity, preventing infections, and reducing the risk of diet-related noncommunicable diseases (1). A diet consisting of lower-quality foods, such as highly processed snacks, sugary drinks, white grains, refined sugar, fried foods, foods high in unhealthy fats, and high-glycemic foods like potatoes can lead to weight gain, obesity and other chronic conditions such as diabetes, cancer, heart diseases, and stroke (2–4). Conversely, high-quality foods consist of unrefined, minimally processed options like vegetables, fruits, whole grains, nuts, pulses, healthy vegetable and seed oils, healthy fats, and healthy sources of plant and animal proteins (3, 5). Consuming high-quality foods in appropriate portions helps in maintaining good health and attaining an ideal body weight without obesity, while also reducing inflammation within the body (3, 6).

In the past, the absence of a single, validated index to assess diet quality in low- and middle-income countries has led to the utilization of proxy measures like dietary diversity scales. However, in recent years, standardized tools like the Global Dietary Quality Score (GDQS), has emerged to measure diet quality (7, 8). A lower score has been linked to an increased risk of obesity and its related complications, whereas higher scores have been associated with more favorable anthropometric measurements, including lower body mass index, waist-to-height ratio, and waist circumference (9, 10).

Globally, the prevalence of overweight and obesity has increased in the last few decades, including in low- and middle-income countries (11). As the global prevalence tripled between 1975 and 2016, the same pattern continued in many African countries, including Ethiopia (12, 13). It caused 2.4 million deaths and 70.7 million disability-adjusted life years among females in 2017 in the world (14). Overweight and obese women are at risk of chronic diseases, untimely death, mental disorders, postpartum bleeding, and fetal macrosomia (15, 16).

The fundamental cause of overweight and obesity is an energy imbalance between calories consumed and expended (12). It is also well-established that unhealthy eating pattern leads to weight gain (17). Furthermore, overweight and obesity were associated with advancing age, urban residence, female gender, better educational status, and being in the affluent quintile (18, 19). Recent evidence indicates an inverse association between healthy diets, overweight, and obesity (20).

The role of dietary protein in the development of obesity is controversial. Some studies indicated that excess protein intake beyond recommended daily requirements may increase fat-free mass and adiposity, with a high potential to increase BMI (18). On the other hand, high protein and low carbohydrates resulted in significant weight loss among obese adults in interventional studies (21, 22).

In recent years, plant-based proteins have been considered a healthy option to meet the body’s protein demands (23). Plant-based proteins are a significant source of dietary protein, calories, and minerals in many low- and middle-income settings. Though people who consume more plant-based staple foods were challenged by low protein quality (24) and had lower muscle mass index (25), it has also had positive outcomes. For instance, people who obtain protein from plant source has a lower risk of hypertension, cardiovascular disease, metabolic syndrome, and type-2 diabetes (23, 25).

Animal-source proteins (ASP) are energy-dense and contain readily digestible protein along with micronutrients (minerals including iron, zinc, calcium, and vitamins such as vitamins B-12, vitamin A, and riboflavin) that are essential to meet the body’s requirements (26). However, evidence indicates that excess consumption of ASP is associated with hypertension, cardiovascular diseases, type-2 diabetes, and metabolic syndrome (23, 25, 27). On the other hand, a diet rich in plant-based proteins but low in animal-source protein is essential to maintain a healthy condition (28).

Understanding the usual protein intake and other macronutrients among women of reproductive age is essential for evaluating their nutritional status (29). In Ethiopia, there is limited evidence on the effect of dietary protein intake on women’s body mass index. Therefore, this study investigated the association between dietary protein intake, diet quality, and overweight and obesity among women in Kersa district, Ethiopia.

This study found that 7.5% of reproductive-age women in Kersa were overweight and obese. The recommended minimum dietary diversity of five or more food groups out of 10 per day was achieved by only 24.5% of women. Global Diet Quality Scores show 28, 70.8, and 1.2% of participants had a low, moderate, and high risk of nutrient adequacy and diet-related non-communicable diseases. Being overweight and obese was inversely associated with dietary protein intake per kilogram of body weight in adjusted models. Similarly, advancing age, non-farmers, higher consumption of food from unhealthy groups, and high fat intake were associated with overweight and obesity. Lastly, the study identified moderate dietary protein intake, non-farming occupation, middle age, better education, and wealth determinants of adequate diversity score.

The predominantly rural Kersa HDSS exhibited a higher prevalence of overweight and obesity (7.5%) among women of reproductive age compared to the national prevalence of 4% for rural residents in Ethiopia in 2016 (43). Notably, reports indicate a consistent rise in the prevalence of overweight and obesity in this age group, increasing from 3% in 2000 to 8% in 2016 in Ethiopia (44). The prevalence of overweight and obesity reached an alarming level in some developing countries such as 50.4% in Tanzania (45), 35.2% in Bangladesh (46), and 55.20% in Brazil (47). This shows the urgent need for targeted interventions and policies to address this growing issue and improve the health outcomes of women and their children.

In the current study, moderate and higher dietary protein intake is associated with low BMI among women of reproductive age. This is in line with similar studies that the consumption of high-protein diets produced more significant weight loss, lower BMI, loss of fat mass, and preserved lean mass compared with the consumption of normal-protein diets (48, 49). Unlike high fat and high carbohydrates (50), high protein intake, especially plant-based, does not result in excess energy and weight gain (51). Dietary protein is protective against overweight and obesity because it promotes satiety, energy expenditure and changes body composition in favor of fat-free body mass (52). However, the majority of reproductive age women in Kersa experience energy deficiency, which can be attributed to factors such as low socio-economic status, limited access to nutritious and diverse food options, and inadequate access to clean water and sanitation facilities. These factors can compromise the health and energy levels of women.

This study revealed that total carbohydrate intake has a weak but positive association with overweight and obesity among women of reproductive age. In this rural area, three fourth of energy was derived from carbohydrates such as foods made from cereals. However, in the body of the literature, there are controversies in selecting carbohydrates for weight reduction and reducing the risk of NCDs (53). On the other hand, a combination of low carbohydrates and high protein is emerging as an intervention to reduce body weight (54). Consistent with a critical review, women who consumed higher protein diets were less likely to be overweight and obese (55). This is due to high protein diets causing an increase in thermogenesis, decrease in fat absorption, and increase in fecal fat excretion (dairy products) or altering the intake of other nutrients, including carbohydrates and fats (56).

According to this study, the median dietary protein consumption for women in Kersa was found to be 0.8 grams per kilogram of body weight per day. This is slightly lower than the World Health Organization’s recommendation of 0.83 grams per kilogram of body weight per day to meet the needs of 97.5% of a healthy adult population. The study also found that lactating mothers in Kersa had slightly lower average daily dietary protein and energy intake compared to non-lactating women. This is in contrast to the WHO’s recommendation that lactating women should consume an additional 19 grams of protein per day in the first 6 months postpartum and 12.5 grams of protein per day after 6 months (57). Additionally, breastfeeding women are advised to consume an extra 500 kilocalories per day to compensate for the energy cost of lactation, in addition to the recommended energy intake for non-pregnant women (58).

The GDQS and dietary diversity are two important factors that are often associated with overweight and obesity. In Kersa, a unit increase in the consumption of food groups categorized as unhealthy or unhealthy in excessive amounts (GDQS-), increased the likelihood of overweight and obesity in 30% but dietary diversity was not associated with overweight and obesity. This is compatible with other similar studies (59, 60). However, some studies shows that higher dietary diversity increases the odds of obesity and overweight (61–63). It is important to be cautious when promoting health messages to the community, as consuming energy-dense foods from a variety of groups can lead to weight gain and obesity. On the other hand, women with lower are more likely to be overweight or obese, while those with higher GDQS have a lower risk (20, 59). Therefore, it is important to strike a balance between a high GDQS and appropriate dietary diversity in order to maintain a healthy weight and prevent overweight and obesity.

This study has provided valuable insights into the dietary protein intake and body mass index of reproductive-age women in Kersa. However, it is important to acknowledge that there are limitations to this study. Like all cross-sectional designs, it does not allow for causal inferences to be made. Therefore, future longitudinal studies should be conducted to examine dietary protein intake, as well as other macronutrients, energy intake, diet quality, and the entire range of body mass index in a similar population. Additionally, it is crucial to consider other factors such as lifestyle and behaviors, as the complex etiology of obesity cannot be fully explained by dietary protein intake alone. Lastly, it is worth noting that the Ethiopian food composition table did not include all the food items consumed in Kersa, so the Tanzanian food composition table was also used for missing food items. This may result in some differences in nutrient content between the two countries.

The study indicated an inverse relationship between body mass index (BMI) and dietary protein intake. It also revealed that women who consumed foods from unhealthy or unhealthy when consumed in excessive amount group were more likely to be overweight or obese. By increasing dietary protein consumption, reproductive age women can minimize the odds of becoming obese or overweight. Furthermore, it is crucial to implement interventions that encompass community-based educational programs that promote healthy eating, policy that support healthy food choices and increase accessibility of protein rich foods, and healthcare services to provide regular health screenings for women to identify underlying health concerns related to weight management and offer personalized guidance on incorporating dietary protein into their diets.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.

The studies involving humans were approved by Institutional Health Research and Ethics Review Committee of College of Health and Medical Sciences, Haramaya University. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

AR: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. NA: Conceptualization, Data curation, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – review & editing. KR: Conceptualization, Data curation, Investigation, Methodology, Software, Supervision, Validation, Visualization, Writing – review & editing. YD: Conceptualization, Data curation, Investigation, Software, Supervision, Validation, Writing – review & editing. EH: Conceptualization, Data curation, Investigation, Methodology, Software, Validation, Visualization, Writing – review & editing. WF: Conceptualization, Data curation, Funding acquisition, Investigation, Methodology, Software, Supervision, Validation, Visualization, Writing – review & editing.