Healthy diets and zero hunger are critical components of sustainable development and poverty reduction targets. According to the United Nations (UN), healthy diets promote overall health and wellbeing and help to prevent chronic diseases, such as obesity, diabetes, and heart disease (1). Similarly, zero hunger is essential for achieving food security, eliminating malnutrition, and eradicating poverty (1). However, despite the global effort to achieve healthy diets and zero hunger, the prevalence of malnutrition and food insecurity remains high in low- and middle-income countries, including Nigeria (2).

From a global perspective, the food system has been weakening over the years owing to multidimensional shocks and other unexpected events, and this situation has exacerbated the systemic issues that are threatening food security and weakening the resilience of the food system (3). The countries' ranking on the Global Food Security Index (GFSI) reveals that the global food environment is seriously deteriorating. Sadly, Nigeria is among the last four weakest performers and bottom-ranked countries with a very low GFSI of 42 points score in the latest ranking. In sub-Saharan Africa, Nigeria is also among the bottom 10 countries whose food security situation is worse (3). This has also contributed to the awful performance of Nigeria in the latest Global Hunger Index (GHI) ranking, which currently stands at a global hunger index score of 27.3 (4).

In recent times, the progress recorded against hunger has largely been stagnated and even worsened in many nations across the world, especially on the prevalence of undernourishment, which reveals a skyrocketing figure of people who do not have regular access to sufficient calories, with as many as 828 million individuals undernourished (4, 5). From a regional perspective, vulnerable populations in sub-Saharan Africa and some other parts of Africa are the most at risk of increased undernourishment because of the persistent unrest and conflicts, as well as other underlying factors in this region, and the proportion of people facing hunger in Congo, Ethiopia, and Nigeria, in particular, is continually increasing (6). Apparently, this threatens the progress toward the ambitious goal of ensuring access to adequate food and healthy diets for all.

In the real sense of it, more than half of the world's population cannot afford a healthy diet (7). In Nigeria, the cost of a healthy diet in Nigeria is approximately $4.1 per person per day, and given this metric, in Nigeria, the percentage of the population who are unable to afford a healthy diet is 95.9% (7). Globally, in approximately 52 countries, where most are residents of Africa, over half of the estimated inhabitants cannot afford a healthy diet (7). While hunger is a global phenomenon, it is particularly acute in African countries. In many countries across sub-Saharan Africa, more than 90% of the population cannot afford a healthy diet. Sub-Saharan Africa is particularly susceptible to extreme climate events and the resulting volatility in food prices is due to the disruption in the supply chain (7–10). This has led to serious inflationary effects in the prices of food items across many African countries, including Nigeria. This evidence suggests that the likelihood of having more people who are unable to afford healthy diets is very high.

Malnutrition and food insecurity are significant public health challenges in Nigeria, and the prevalence of undernutrition is high, with 37% of children younger than 5 years stunted, and 17% wasted (11). Similarly, the prevalence of overweight and obesity is increasing, with 20.8% of adults overweight and 8.5% obese (12). Furthermore, the Food and Agriculture Organization (FAO) estimates that 22.5% of the Nigerian population is food insecure, with more than 90 million people experiencing moderate to severe levels of food insecurity (2). Notable studies have also shown that unhealthy diets and food insecurity are associated with poverty, low education, and poor access to healthy foods (13, 14). The availability and accessibility of healthy foods have been identified as critical determinants of healthy diets and zero hunger (15, 16). However, few notable studies (17–20) have examined the pattern of healthy diets and zero hunger among households in Nigeria.

South-West Nigeria is one of the regions in Nigeria with a high prevalence of malnutrition and food insecurity (2). Malnutrition affects both children and adults, with the highest prevalence among the rural population and low-income households (11). Similarly, food insecurity is prevalent in the region, with many households experiencing inadequate access to food and poor dietary diversity (2). The pattern of healthy diets and zero hunger among households in Africa and, in particular, Nigeria is influenced by several factors. These factors include sociodemographic characteristics, such as income, education, and occupation, as well as environmental and structural factors such as the availability and accessibility of healthy foods, food prices, and food systems (15, 18, 20–22). For instance, households with higher income and education levels are more likely to consume a healthy diet than those with lower income and education levels (21). Similarly, the availability and accessibility of healthy foods in the local food environment are essential for promoting healthy diets and reducing food insecurity (15).

According to Erhabor and Ojogho (23), as well as (24), rice is a staple food crop consumed by nearly every household, but with the recent development of encouraging local production in the nation, Ofada rice represents a good option to focus on owing to its nutritive value which is essential for a healthy diet (24). In Nigeria, efforts to promote healthy diets and zero hunger have been made through various policies and programs. For example, the National Food and Nutrition Policy was launched in 2016 to promote healthy diets and improve nutrition in the country (25). Similarly, the National Social Safety Net Program was established to provide cash transfers to vulnerable households to improve their access to food (26). Meanwhile, the impact of these policies and programs on the pattern of healthy diets and zero hunger among households in South-West Nigeria is largely unfelt, as a majority of the households are finding it difficult to have a healthy diet. Therefore, this study aims to contribute to the existing knowledge by examining the pattern of healthy diets and zero hunger among households in the region, given the consumption expenditures and budget shares by households on various mixtures of food items.

This study was conducted in the South-West region of Nigeria. The region is one out of six geopolitical zones in the country. The South-West region lies between longitude 2⁰ 31¹ and 6⁰ 00¹ East and latitude 6⁰ 21¹ and 8⁰ 37¹N and has a total land area of approximately 77,818 km². It shares boundaries in the west, south, east, and north with the Republic of Benin, Gulf of Guinea, Edo and Delta States, and Kwara and Kogi States, respectively. South-West Nigeria's climate is tropical in nature and experiences both rainy and dry seasons. Data were collected with the use of a well-structured questionnaire administered to the representative sample selected for this study. A multistage sampling technique was employed to select the respondents in the study area. The study purposively selected three states, namely, Lagos, Osun, and Ogun because of the predominance of local (Ofada) rice farmers in the areas. The purposive selection was also adopted in the second stage to select two local government areas (LGAs) from each of the selected state. The third stage involved a random selection of two wards, each from the two selected LGAs in each of the states, making it four wards from each selected state based on a lucky-dip approach (24, 32). The final stage used a random proportionate-to-size sampling technique to select 600 respondents (households) from all the chosen LGAs. This was applied because of the population variation that exists across the villages in the selected LGAs. Hence, this represents the representative sample used for the research.

This study collected information on the following commonly consumed food items: rice (Main staples), Maize (Main staples), Yam tuber (Main staples), Yam flour Main staples, Beans (Pulses), Cassava-Gari (Main staples), Plantain (Fruit), Vegetable (Vegetables), Fruits (Fruit), Meat (Meat and fish), Beverages (Condiments), Fats and Oil (Oil). According to World Food Programme (33), the food items are broadly grouped into different food groups, as shown in parentheses beside the food items. This also requires further analysis of attaching weights and measurements if the study is interested in the food consumption score of the sampled households, which is outside the scope of this study. Hence, the main focus of this study was on the budget share analysis of these food items and to mirror the households' pattern of consumption expenditure on the food items using budget share analysis.

The results of expenditure, own-price, and cross-price demand elasticities (both uncompensated and compensated) are presented sequentially.

The result in Table 1 revealed that the households' budget shares on local rice in Lagos, Ogun, and Osun States were 0.11, 0.14, and 0.09, respectively. This implies that 11%, 14%, and 9% of the households' food expenditure were spent on local rice consumption, and from a general perspective of rice consumption (both local and foreign), approximately 19.5%, 23%, and 17.5% of the budgets were expended for the period under consideration. The households' budget share on local rice for the aggregated households of the study is 0.11, which indicates that households spent 11% of their food expenditure on local rice variety and 19.5% of food expenses on both local and foreign rice consumption. However, 19.5% of households' expenditure on both local and foreign rice was found to be below that of the North-West geopolitical zone, and the nation's average was reported to be 28.39% and 30.63%, respectively (37). The highest budget share is associated with rice consumption (19.36%), and the lowest budget share is associated with plantain (1.91%). The budget share of fat and oil stands at the second highest. Households' total expenditure for all of the food items considered for the study is N=79,651,455 ($218,223) for the period under review. This finding lends credence to the growing trend in households' rice consumption preference over other food items and therefore, the central position of rice in households' food basket. The higher proportion of households' expenditure on rice, both local and foreign varieties, agrees with Omonona et al.'s study (38) and Erhabor and Ojogho (23) also established that rice had the highest proportion of households' monthly food expenditure relative to other food items in their study. The implication is that sudden changes in households' food expenditure would affect the households' rice consumption.

Given the observation on the budget share attached to the prevalent food items consumed by households in the study area, one can infer that a large proportion of the budget was expended on the main staple food items, suggesting that there was no significant diversity in the food item matrix of the household. Evidently, this can have implications on the health outcomes of the household members and ultimately lead to a serious healthy diet crisis.

This study underscores the importance of having access to good-quality and healthy foods by people to cater to their dietary needs, given various mixes of food items required for adequate human functionality in society. The research probed on the consumption-expenditure pattern and households' budget shares on various food items commonly consumed by people through the estimation of households' price and demand elasticity which only a few studies have dealt with in the past using other study locations, different from this study area. Besides, most of this study used the QUAIDS model, while this study applied an extended version of the model known as the LA-QUAIDS model. This is very important to guide the policy maker in the design and implementation of necessary policy actions that can encourage domestic production, increase food distribution and supply, and ultimately reduce the market prices of locally produced food items; all aiming at self-sufficiency in local food production.

This study used a linear approximated QUAIDS model to analyze households' demand for local rice in the South-West region of Nigeria. The findings from this study reveal that households in Nigeria consume local rice to a reasonable extent and that local rice does not represent a luxury good based on the calculated expenditure elasticities because they are all expenditure inelastic. Uncompensated and compensated own-price elasticities of demand for 9 (9) out of 13 food items are negative, which is consistent with demand theory, and they are statistically significant. The value of compensated and uncompensated own-price elasticities for local rice was found to be −1.64 and −1.69, respectively, which suggests that local rice is price-sensitive. That is, consumers are likely to be affected by any changes in the price of local rice. In light of the findings of this study, it is recommended that adequate policy aimed at boosting local rice production and increasing its supply should be pursued. This could invariably connote a price-reduction strategy, by default. Suffice to say that increased supply will force down the price of local rice because the food crop was shown to be own-price elastic.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by University Research Ethics Committee. The patients/participants provided their written informed consent to participate in this study.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.