This study is one of the first to provide evidence of a nationwide prevalence and factors associated with underweight, overweight, obesity, and overnutrition among 15-49-year-old women of reproductive age in Sierra Leone (Tables 1, 2 and 3; Fig. 1). To ensure the optimum generalizability of our findings, we used nationally representative data from the Sierra Leone Demographic Health Survey of 2019 (SLDHS-2019) [20, 25].

Specifically, this study determined the prevalence of underweight, overweight, obesity, and overnutrition among women of reproductive age (15–49 years) in Sierra Leone, with underweight at 6.7%, overweight at 19.7%, obesity at 7.4%, and overnutrition at 27.1%.

The prevalence of underweight was lower than studies conducted in other sub-Saharan African countries, for example, Kenya (9%) [29] and Tanzania (10%) [30], but similar to a study conducted in Nigeria (6.7%) [31]. This prevalence is also within the range of (5 to 20%) for women of reproductive age (15–49 years) in the African continent [31].

The observed variance in the prevalence of underweight in Kenya, Nigeria, and Tanzania were likely due to differences in characteristics of study participants, such as age and food security status [31].

In a Nigerian study by Senbanjo et al., only women aged 15–39 years from one state of Lagos were included in the survey, while the other two studies from Tanzania and Kenya included ages of 15–49 years, like ours [31]. Another study in the East African region found that Uganda, a country with the lowest food insecurity, had a lower prevalence of underweight among women of reproductive age than Tanzania and Kenya [32]. Compared to Asian countries, the Sierra Leone prevalence rate of underweight at (6.7%) is lower than Indonesia at (11.2%) [33] and Bangladesh at (30.4%) [32].

Therefore, the observed differences in the prevalence of underweight among women of reproductive age in the five countries of Uganda, Kenya, Tanzania, Nigeria, and Sierra Leone were likely due to differences in characteristics of study participants, such as the country of origin and their food security status.

The finding in the current study that the prevalence of underweight was highest among 15-24-year-olds (11.9%) and lowest among women of 25–34 years (5.6%) could be that young women have increased nutritional demands, have food insecurity, or have unhealthy feeding habits thus increasing their vulnerability to underweight.

A study by Akseer et al. showed that younger adolescent mothers (< 20 years) were more likely to be underweight than older mothers (20–49 years) in Afghanistan because of increased mother-to-child nutritional demands and increased nutritional requirements of adolescent mothers [34].

Furthermore, our study revealed that respondents of the age group (25–34 years), residing in the North of Sierra Leone, not listening to radios, and unmarried/single were significantly less likely to be underweight (Table 4). Also, the study found that parity, residency (rural versus urban), female-headed households, household size, work status, level of education, wealth indices, reading magazines, smoking cigarettes, and alcohol use were not significant correlates of underweight in this study population (Table 4).

Contrary to our findings, previous research found a significant association between lower socioeconomic status and underweight [35,36,37]. One possible explanation is the difference in methods used for measuring economic status, with the current study limiting it to the number of adult household members, assets, and property. In contrast, other researchers have used more composite economic indicators [35,36,37].

Also, findings of a double burden of malnutrition that is underweight (6.7%) and overnutrition (27.1%) in Sierra Leone, a low-income country (Table 7), are not unique but are worrisome as policymakers will need to design comprehensive public health programs that address the extremes of malnutrition. The co-existence of underweight and overnutrition has been reported in many low-income countries in the Asian Pacific region [38] and in low-to-middle-income countries, including sub-Saharan Africa [9,10,11,12,13,14]. The evidence of underweight, overweight, obesity, and overnutrition are in this study in Sierra Leone.

Many studies suggest that a rapid dietary and lifestyle transition is the leading path for the double burden of malnutrition, with an increase in overnutrition and diet-related non-communicable diseases (NCDs) [38, 39]. We, the authors, propose a need for increased efforts on policy initiatives and lifestyle changes in Sierra Leone to combat the double burden of malnutrition, which is highly prevalent in the country.

In addition, the predictors of overweight, obesity, and overnutrition among the study population include age groups of 25–34 years and 35–49 years, unmarried/single women, working-class women, women from the North and South of Sierra Leone, middle, richer, and richest wealth indices; and not listening to radios. The predictors of obesity and overnutrition were like that of overweight, with the addition of female-headed households.

The current study finding that overweight, obesity, and overnutrition were more prevalent in the older age groups is consistent with previous studies [40,41,42]. However, contrary to previous studies [40, 41, 43], associations between higher economic status (richer and richest wealth indices), educational level, and residing in urban areas with being overweight or obese were not statistically significant in this current study.

Of concern was that (18.7%) of young girls and women aged 15–24 was overnourished, indicating a large proportion of overweight and obese women in early adulthood. This finding means that overweight and obesity investigations following the lifecycle of women in Sierra Leone should be prioritized, as in many low-to-middle-income countries [43].

In terms of dietary behaviors, previous research found inadequate fruit and vegetable intakes [44, 45], eating occasions away from home [46], high salt intakes [47], consumption of ultra-processed foods, and saturated fats as independent predictors of obesity [48]. However, our current study being a secondary data analysis from the SLDHS-2019, we could not assess the associations between dietary behaviors such as frequency of snacking, skipping breakfast, high intake of sugary beverages, and overweight or obesity [45, 49], and overnutrition among the study population.

Unlike previous research [50,51,52], this study showed no associations between current tobacco and alcohol use and the prevalence of overweight, obesity, and overnutrition among the study.

Our study found that working-class women were less likely to be overweight but had no association with obesity and overnutrition among respondents. Previous studies from Addis Ababa, Ethiopia, reported higher figures for overweight and obesity, ranging from (26.7 to 38%) among workers in the Wonji Shewa sugar factory [53,54,55,56]. The availability of more energy-dense fast foods and exposure to sedentary life in Addis Ababa and its surroundings (compared to other urban settings) explains the high figures for overweight and obesity in Ethiopia [53,54,55,56]. The observed overweight and obesity among sugar factory workers in Ethiopia was likely because of their unfettered access to cheap and free sugar from their workplace.

Scholars, academicians, and health specialists have reported that sedentary life alone may not be the only reason for high rates of overweight and obesity as it is becoming clear that physical exercise alone does not contribute to weight loss, much as exercise is a healthy lifestyle. This finding in Sierra Leone on overnutrition at (27.12%) is lower than most studies in Ethiopia [55,56,57,58]. The Sierra Leone finding is also lower than other studies based on DHS data from Nigeria (26.7 and 36.4%) [57, 58] and seven African countries (average prevalence of 31%) [59]. It is also lower than other studies conducted in Benin (41.3%), South Africa (56.6%), Iran (61.3%), and India (75.33%) [60,61,62,63]. Therefore, this current study’s findings may differ due to disparities in dietary patterns, lifestyles, level of urbanization, and economic development in Sierra Leone.

Of particular interest in this Sierra Leone study was that it was less likely to have overweight women among the working class, contrary to findings from other African countries. We, the authors, have asked many questions about whether there is something we can learn from the results among women in Sierra Leone that can be replicated elsewhere in Africa. Could there be some dietary discipline and good dietary habits among working-class women in Sierra Leone? This question can only be answered by conducting a comprehensive qualitative study on working-class women in Sierra Leone on their dietary habits and discipline.

In addition, the current study found that the age of women, marital status, wealth indices, working-class women, female-headed households, and residence in the North and South of Sierra Leone were significantly associated with overweight, obesity, and overnutrition among women of reproductive age. Consistent with other studies, this study’s results demonstrate that overweight and obesity are higher among older women [64,65,66,67,68]. A decrease in levels of physical activities and higher intakes of energy-dense foods as the age of women advances is suggested as a possible explanation [69].

In contrast, being overweight, obese, and overnourished was less likely among women in the middle, richer, and richest wealth indices in Sierra Leone women. This finding is inconsistent with studies from Addis Ababa and Wonji Shewa sugar factory [51, 64, 65] and elsewhere [61,62,63, 66, 67].

In developing countries, wealthier women are more likely to consume more energy-dense foods and follow a sedentary lifestyle; hence, they are more likely to be overweight, obese, and overnourished [61,62,63,64,65,66,67]. However, this was not the case in Sierra Leone, where overweight, obesity, and overnutrition were less likely among working-class women of reproductive age (15–49 years). As authors, we believe there is a need to explore these unique findings among women in Sierra Leone in future studies.

Furthermore, previous studies showed that the prevalence of overweight, obesity, and overnutrition was significantly higher among working women with higher educational levels [67, 68]. However, a higher educational level was not statistically significant in our study population except for the crude odds ratios for respondents with a primary level of education and obesity.

Our current study finding on the level of education and association with obesity contrasts with other studies where a higher educational level is associated with obesity [67,68,69]. This finding on obesity in different settings may be a result of changes in lifestyles as disposal income rises; these classes of women tend to go for processed carb diets and more sugary drinks, including drinking tea three to four times a day with bread with a shift from manual labor to more sedentary occupations and the related decline in physical activities.

In contrast to other studies, the unmarried/single women in the current study were independent predictors of overweight, obesity, and overnutrition [70,71,72]. Previously, married women were more likely to have higher parity, resulting in adopting a more sedentary lifestyle and eating high-energy foods, usually offered to women during the postpartum period, thus becoming overweight or obese. On the contrary, we found that unmarried/single Sierra Leone women were more likely to be overweight, obese, and overnourished.

On this finding, we, the authors, suggest that perhaps many unmarried/single women in Sierra Leone lead a more sedentary lifestyle, have a higher energy-rich diet, and are from the northern region, and this may, in part, explain the associations between the unmarried/single with overweight, obesity, and overnutrition among women in the reproductive age in this country. These authors cautiously recommend further studies to determine why single/unmarried women were more likely to be overweight, obese, and overnourished in Sierra Leone compared to findings from other countries in Sub-Saharan Africa.

Our current study found that better wealth indices and female-headed households were less likely to be associated with overweight, obesity, and overnutrition among women of reproductive age (15–49 years) in Sierra Leone.

Although there are cross-country differences, the number of populations living in female-headed households and households headed by women has risen over the years [73]. Current data show that the probability of a woman aged fifteen or older in households, controlling for her age, has been increasing since the early 1990s in all regions and across the entire age distribution in Africa [73].

Using a complete series of DHSs fielded in Africa over the last 25 years and covering 89% of Africa’s population, recent research has investigated Africa-wide changes in the prevalence of female-headed households [73]. The result suggests that economic growth brings more female headship, presumably due partly to lower work-related migration by men but associated with a growing local economy [73].

The seeming paradox that female headship is rising during a period of growth is that other things are also changing across Africa [73]. Changes in the demographic and population characteristics, social norms, women’s education, and the family’s nature are encouraging female household headships in the African continent [73].

Current reports show that an extra year of schooling produces a three-percentage increase in shares of the population living in female-headed households [73].

In addition, on average, a one-year rise in women’s age at first marriage produces a 2.5%-point increase in the share of the population living in female-headed households, an effect almost as strong as an extra year of schooling [73]. Life expectancy’s positive impact equals a 0.5%-point boost per additional year among women, presumably reflecting the natural survival advantage of women with higher overall life expectancy and the resulting incidence of widow-headed households [73].

Furthermore, conflicts, wars, and HIV and AIDs in many communities in the African continent have raised many countries’ share of the population in female-headed households [73]. Thus, female-headed households’ prevalence has been rising while poverty has been falling in Africa [