Visualizing changes over time of the prevalence of undernourishment

Using {ggplot2} to create a line plot for the evolution of food security in the world

About the data

Set-up

library(tidyverse) 
library(ggplot2)
library(showtext) 
library(ggtext)
library(geomtextpath)

Loading data from FAO

food_security <- read.csv("FAOSTAT_data_en_4-27-2025.csv")

Data wrangling

undernourishment <- food_security |>
  filter(Item == "Prevalence of undernourishment (percent) (3-year average)") |>
  filter(Element == "Value") |>
  filter(Area %in% c("Central America", "Caribbean", "South America", 
                     "Northern Africa (excluding Sudan)", "Sub-Saharan Africa (including Sudan)", 
                     "Central Asia", "Southern Asia", "South-eastern Asia")) |>
  mutate(
    Area = fct_recode(Area,
                      `Northern Africa` = "Northern Africa (excluding Sudan)", 
                      `Sub-Saharan Africa` = "Sub-Saharan Africa (including Sudan)"),
    Value = as.numeric(Value)/100,
    Year = fct_recode(Year, 
                      `2001` = "2000-2002", `2002` = "2001-2003", `2003` = "2002-2004", `2004` = "2003-2005", `2005` = "2004-2006",
                      `2006` = "2005-2007", `2007` = "2006-2008", `2008` = "2007-2009", `2009` = "2008-2010", `2010` = "2009-2011", 
                      `2011` = "2010-2012", `2012` = "2011-2013", `2013` = "2012-2014", `2014` = "2013-2015", `2015` = "2014-2016", 
                      `2016` = "2015-2017", `2017` = "2016-2018", `2018` = "2017-2019", `2019` = "2018-2020", `2020` = "2019-2021",
                      `2021` = "2020-2022", `2022` = "2021-2023"),
    Year = as.numeric(as.character(Year))
    )

Set theme settings and define fonts, colors, and text to be used in the waffle chart

 my_theme <- function() { 
   
   theme_minimal(
    base_family = "fjalla"
    ) + 
  
  # Custom format
  theme(
    # Title setting
    plot.title = element_text(
      color = "black",
      size = 18
    ), 
    plot.title.position = "plot", 
    
    # Subtitle setting
    plot.subtitle = element_text(
      color = "grey50",
      size = 14
    ), 
    
    # Axis settings
    axis.title = element_text(
      color = "black",
      size = 11
    ),
    
    axis.text = element_text(
      color = "grey50",
      size = 11
    ),
    
    axis.ticks = element_line(
      size = 1.25, 
      color = "black"
      ),
    
    axis.line.x.bottom = element_line(
      color = "black",
      size = 1.25
      ),
    
    axis.line.y.left = element_line(
      color = "black",
      size = 1.25
      ),
    
    # Panel
    panel.grid = element_blank(),
    
    # Caption settings
    plot.caption.position = "plot", 
    plot.caption = element_markdown(
      size = 10,
      hjust = 0
      ),
    
    # Background
    plot.background = element_rect(
      color = "#FFF5EB",
      fill = "#FFF5EB"
      )
    )
 }

Create the line chart

# Plot
font_add_google("Fjalla One", "fjalla")

showtext_auto()

ggplot(undernourishment) +
  geom_line(
    linewidth = 1.5,
    aes(x = Year,
        y = Value,
        color = Area, 
        group = Area)
  ) + 
  
  scale_color_manual(values = c("#B2432F", "#DB735C", 
                                "#919C4C", "#9B5672",
                                "#B58900", "#3A6589",
                                "#6F5438", "#828585")) + 
  
  scale_y_continuous(
    labels = scales::label_percent()
    ) +
  
  scale_x_continuous(
    expand = expansion(add = 0.8),
    breaks = 2001:2022
  ) + 
  
  geom_textpath(
    text_only = TRUE,
    spacing =  50,
    data = filter(undernourishment,
                  Area %in% c("Sub-Saharan Africa", "Caribbean", 
                              "Southern Asia", "Central Asia")
    ),
    aes(x = Year,
        y = Value,
        color = Area,
        label = Area), 
    vjust = -0.5, 
    hjust = 1, 
    size = 3) +
  
  geom_textpath(
    text_only = TRUE,
    spacing =  50,
    data = filter(undernourishment,
                  Area %in% c("South America", "Central America", 
                              "Northern Africa")
    ),
    aes(x = Year,
        y = Value,
        color = Area,
        label = Area), 
    vjust = -0.5, 
    hjust = 0, 
    size = 3) +
  
  geom_textpath(
    text_only = TRUE,
    spacing =  50,
    data = filter(undernourishment,
                  Area == "South-eastern Asia"
    ),
    aes(x = Year,
        y = Value,
        color = Area,
        label = Area), 
    vjust = -0.5, 
    hjust = 0.5, 
    size = 3) +
  
  guides(color = "none") +
  
  labs(
    title = "Prevalence of undernourishment by region | 2001-2022",
    subtitle = "Proportion of the population with a dietary energy consumption below the minimum required for maintaining a healthy life and carrying out a light physical activity",
    caption = paste0(
      "<span style='color:black;'>Source:</span> <span style='color:grey50;'>FAO Statistics Division</span>",
      "<br>",
      "<span style='color:black;'>Plot:</span> <span style='color:grey50;'>Juan Torres Munguía</span>"
    ),
    x = "",
    y = ""
  ) + 
  my_theme()

Save the line chart as an image

showtext_opts(dpi = 320)  
ggsave(
  "undernourishment.png",
  dpi = 320,
  width = 14,
  height = 7,
  units = "in"
)