1. Introduction

Consumption of staple foods such as rice, maize and cassava is very high in low- to middle-income countries ^[1][2][3][4][14,18,19,20], while middle- to higher-income countries are consuming fewer staple foods and changing their consumption patterns towards more meat, processed foods and dairy products ^[1][5][6][7][14,21,22,23]. However, changes in dietary patterns are influenced by per capita income, lifestyle/preferences, urbanization and economic development ^{[1][8][9][10][11][12][13][14][15]}[14,24,25,26,27,28,29,30,31], resulting in a high demand for land resources ^[14][30] to cope with the diverse food consumptions. Such changes in dietary patterns are also known to increase greenhouse gas emissions, impact the climate, contribute to unbalanced dietary intake and health-related diseases, as well as further increasing pressure on ecosystem carrying capacity and land degradation ^{[16][17][18][19][20][21][22]}[32,33,34,35,36,37,38]. Besides, the total land required for food is determined by the type of food, the quantities consumed and the size of the population ^[23][39]. Available studies state that the type of food determines the land requirement for food ^[23][39] more than the quantities of food consumed per capita ^[24][40], while others assume that the land requirement for food also depends on the yield per hectare ^[25][41]. An example of this is the fact that an average Indian diet requires less land than an average diet in the United States of America, despite the size of the population ^[24][40].

Land requirements for food have been analyzed at global, regional ^[26][27][42,43], country and rural levels ^{[25][28][29][30][31]}[41,44,45,46,47] using models and thought experiments such as ALBIO (Agricultural Land use and BIOmass), the Human Appropriation of Land for Food (HALF) Index, questionnaires, household food consumption surveys, data on population, dietary habits and crop yields. Their studies concluded that our food choices affect the land used for agriculture, i.e. the land required for food depends on the type of food and the rate of change in food consumption patterns. However, this interaction is causing biodiversity to decline at an accelerating rate.

2. Food Consumption Patterns

2.1. Food Consumption Patterns at the National Level

The summary of results as calculated by the FAO food balance sheets indicated that Nigeria’s total food consumption gradually increased from about 260 kg/capita in 2000 to 346.3 kg/capita in 2018, peaking in 2014. Cassava and yam dominated food consumption, followed by rice, maize, tomatoes, and onions, respectively.

Rice, which is the most popular staple, increased from 21.96 kg/capita in 2000 to 39 kg/capita in 2018, while maize showed a significant increased from 17.71 kg/capita in 2000 to 33.7 kg/capita in 2018 (see Figure 14). In as much as the cassava consumption pattern trend was significant, the consumption quantity declined from 140 kg in 2000 to 130.19 kg in 2018. Yam and tomato showed significant per capita increments (74–119 and 9.16–16.61 kg/capita, respectively), while onion consumption was 4.83 kg/capita in 2000 and 6.75 kg/capita in 2018 (see Figure 14).

Figure 14.

 Nigeria food consumption pattern (kg/capita/year) from 2000 to 2018 (FAOSTAT).

2.2. Food Consumption Patterns in the Six Geopolitical Zones

Summarizing the quantities of staple foods consumed (excluding onions and tomatoes) by geopolitical zones in Nigeria, North East and North West lead the way with 2821.22 and 2332.44 kg/year, respectively, albeit mainly from cereals. Following behind are South South (1878.99 kg/year), North Central (1834.28 kg/year), South East (1638.58 kg/year), and South West (689.58 kg/year). However, by per capita consumption derived from their household sizes, South South and South East consumed more food (383.47 and 381.06 kg/capita/year, respectively), followed by North East (357.12 kg/capita/year), North Central (321.80 kg/capita/year), North West (315.20 kg/capita/year), and finally, South West (215.49 kg/capita/year) (see Figure 25). The results of food consumption quantity across the country show that North Central has a 16.4% share of the total average, North East 25.2%, North West 20.8%, South East 14.6%, South South 16.8%, and South West 6.2%.

Figure 25. Pictorial representation of per annum household food consumption distribution and the rate of consumption of staple food (excluding onion and tomato) in the six geopolitical zones.

3. Findings

Food consumption patterns in the six geopolitical zones show that cereals and starchy roots contribute significantly (over 70%) to household calorie requirements. Available studies have shown that developing countries rely on starchy staple foods to meet their energy needs. For example, a similar observation was made in the city of Guyuan in Northwest China that the energy needs of the population are met by staple foods ^[28][44].

The quantity of household food consumption was estimated from household food expenditure and food prices. Therefore, the share of total household expenditure (as a proxy of income) spent on food is an indicator of household food security, and low-income households spend more of their income on providing food ^[32][65]. The Nigeria National Bureau of Statistics revealed that 59.19% was the total expenditure on food in 2019 by households in Nigeria ^[33][66].

The food consumption pattern results indicate that households are changing their dietary patterns due to their high food expenditures. This is observed in the North East and North West, indicating that the two zones are shifting their consumption patterns from rice to maize as a cheaper alternative, likewise in the South East and South South, consuming more dense calories from cassava and yam than rice and maize. Additionally, an interesting observation is that the South West consumes more cereals, especially rice, than its southern counterparts. A plausible reason for this is that the South West have more rice-producing states ^[34][68], which may have influenced the price of rice to be relatively cheaper than in other parts of the country. The North Central zones also consume more amount of cereals and starchy roots as they have the latitude to produce these crops ^[35][69].

Apart from land holdings and suitability for crop cultivation, food culture also has a significant impact on food choices in the country and it may be difficult for households to change their consumption patterns ^[35][69]. For brevity, a culture of making a gelatinized semi-solid paste from these grains and tubers, which are consumed with locally prepared soups by households across the country, is widespread ^[4][36][20,55], and this is consumed more than once a day. This influence of food culture is also documented in various studies in China ^[22][37][38,72].

In terms of land required for food, the country’s specific land requirement for food has increased from 2000 to 2018 (Figure 36). This indicates that food demand and consumption is increasing for Africa’s largest population. Similar observations were made in a study in the Philippines on the increasing population raising land requirements for food ^[30][46]. The Northern zones having a larger household size and population translated to higher land requirements for the food quantity they consumed compared to the Southern zones.

Figure 36.

 National specific and per capita land requirements for food in Nigeria (data source: FAOSTAT).