Metrics for Food Security & Undernutrition

Metrics for Food Security & Undernutrition

Metrics for Food Security & Undernutrtion 2

Outline

• Information requirements for Policy• Approaches to measure food insecurity and

under nutrition• FAO Indicators of undernourishment &

assessment• Household food consumption surveys &

assessment• Childhood anthropometrics & assessment• Food Security Statistics

3

Food Security

• The World Food Summit in 1996: “Food security exists when all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life.”

• Multidimensions : (i) level and stability of food access and availability,

and (ii) adequacy of food use and nutritional status. • Question: How do we measure these dimensions?

Metrics for Food Security & Undernutrtion


Levels of Food Insecurity


Hunger

• Hunger: A sensation of not having enough to eat.

• Extent of hunger: Lack of essential nutrients in the diet ; a major indicator - food energy deficiency.

• Hunger could be due to one’s inability to absorb and use food energy and specific nutrients for body functions = > overall nutritional status is also affected by people’s health.


Information Requirements for Policy

• Estimate of food emergency due to a sudden drop in supply or access to food; people’s immediate needs of essential nutrients to ensure survival.

• Estimate of chronic food insecurity caused by long term food deprivation due to structural poverty and poor nutrition.


Comprehensive Assessment needs

• Measurement: Who are the food insecure? How many are they? Where do they live?

• For effective policies, one needs to know:What causes people to be food insecure? What is the impact of programs and policies to

address their food insecurity?


Approaches to Measure Food Insecurity and Under nutrition

• FAO Indicators of undernourishment

• Household food consumption surveys, and

• Childhood anthropometrics.


FAO Indicator of Undernourishment

• Prevalence of undernourishment:– Proportion of population not meeting minimum

food energy requirements. • Estimator:– Per capita calorie availability,– Inequality in access to those calories among the

country’s population,– Mean minimum amount of calories required.


FAO Indicator

• Data Sources• Food available for human consumption: National

food balance sheets (FBS) = f(production, trade, stock changes, non-food uses, and extra-household waste)

• Per capita calorie availability: Using Food composition tables, convert food quantity into calories divided by the population (per capita dietary energy supply (DES)(kilocalories per day).


FAO Indicator

Inequality in access to calories:• Assume a log-normal distribution function specified

by mean DES and the coefficient of• variation (CV). • CV is derived from sample distributions of calorie

consumption or food expenditures from available household surveys.


FAO Indicator

• Minimum dietary energy requirement (MDER):– Amount of food energy needed, in order to

maintain an acceptable minimum body weight, body composition, and a level of minimum (‘sedentary’) physical activity, consistent with long-term good health.


Food needs

Minimum Dietary Energy Requirement (kcal/person/day)

Country Name 1990-92 1995-97 2000-02 2006-08

Bangladesh 1690 1720 1740 1770Botswana 1760 1790 1820 1840Brazil 1810 1830 1840 1860China 1850 1870 1890 1910India 1740 1750 1760 1780Indonesia 1760 1780 1800 1820Jamaica 1840 1850 1860 1870Japan 1900 1900 1890 1890Jordan 1690 1730 1740 1760Malawi 1690 1700 1690 1700Malaysia 1760 1780 1800 1820Maldives 1660 1690 1750 1800Mali 1750 1750 1760 1770Nepal 1690 1690 1700 1730Pakistan 1690 1700 1720 1740Rwanda 1660 1690 1700 1710South Africa 1850 1870 1890 1900Sri Lanka 1770 1790 1810 1800Thailand 1810 1820 1840 1850Viet Nam 1710 1740 1780 1820Yemen 1630 1650 1670 1700Zambia 1730 1730 1720 1720Zimbabwe 1750 1770 1790 1790

Source: FAO

Metrics for Food Security & Undernutrtion 14Source: FAO

Metrics for Food Security & Undernutrtion 15Source: FAO


FAO Indicator: Assessment

• Objective: Inform the global community about levels and trends of

undernourishment; facilitate global and regional governance of food security.

Track progress towards the first millennium development goal (MDG).

A measure of chronic food insecurity at national levels.Does not provide information on distribution of the

number of hungry.Does not address policy issues.


FAO Indicator: Strengths & Limitations

• Strength:Global coverage• Limitations: Mean dietary energy supply (DES):

How comprehensive is food energy deficiency as an indicator of food insecurity?

How accurate are the estimates? IFPRI study of 12 African countries show FAO numbers to be underestimates.



• Coefficient of Variation:FAO estimate is an overestimate.Most importantly, it is kept invariant though (i) income

and expenditure inequalities have increased in most developing countries between the early 1980s and mid-1990s; (ii) given Engels’ law and growing income, CV in calorie intake would decline.

Conceptually a constant CV implies the premise that undernourishment is a function of DES only.

Is it an appropriate measure? CV is sensitive to shape in the upper end of the distribution.



• Minimum Dietary Energy Requirement (MDER): Consumption level that balances energy expenditure. How valid are the assumptions with respect to different age-gender composition? How good is this approximation?

• Energy Expenditure = Basal metabolic rate (BMR), the energy needed for digesting food, metabolizing food, and storing an increased food intake, and the energy required for performing physical activity; it ranges between 1300 & 1700 kcal/day for adults, depending on age, sex, height, and body weight; an additional 50% for light physical activity for male & female adults.



• Estimates often are not based on current estimates of FBS data but projections.

• Estimates are not robust with respect to DES, CV & MDER parameters.

• The elasticities of the global estimates of undernourished with regard to national DES, CV, and MDER are 4.8, 1.6, and 4.7.



Household Food Consumption Surveys (HFCS)

• Nationally representative household surveys: Designed and undertaken by country’s statistical office, sometimes supported by other national and international organizations.

• Sample size ranges from a few thousand up to more than 100,000 households.

• Generally such survey estimates are available in respective country statistical offices or the World Bank (http://www.worldbank.org/lsms).

• Countries differ with respect to frequency of such surveys; Indian experience and illustrations.


HFCS: Salient Features

• Indian NSS data: Salient Features• Household consumption surveys: – Reference period: HFCS use 14 or 30 day recall

periods for food items; longer recall periods would involve unacceptable inaccuracies. Surveys with shorter recall periods, say a 7-day recall period, are preferable from a nutritional perspective.


HFCS: Salient Features

• Household consumption surveys: – Estimates of undernourishment: Use food

composition tables & convert data on the quantity of different food items consumed to calories to get an estimate of household calorie consumption. By comparing these consumption estimates with energy requirement cutoffs, which consider the age and sex structure of the household, one can identify households with undernourished members.


HFCS: Strengths & Weaknesses

• Strengths: Estimates are relatively more accurate than those from macro

FBS data. Direct estimates. Disaggregate information permits greater precision. No assumption on demographic composition; instead actual

profile is considered in estimation. Permits ‘hunger mapping’, that is, food insecurity profiles across

socioeconomic or geographic divisions . No distributional assumption involved; non-parametric method. Information on socio economic characteristics permit analysis of

determinants of food insecurity.



• Strengths: Permits to estimate income and price responsiveness of food energy and nutrient consumption, a tool required to predict nutritional impacts of policies and external shocks or simulate the impact of food price or food supply shocks on food insecurity by population groups.



• Weaknesses:Single round surveys will not capture seasonal variations;

Solution: Annual survey based on moving reference period.

Estimates for individual households would still be biased.Difficult to estimate calorie intakes from food consumed

outside like restaurants and hostels. Do not capture waste, losses, and non food use within

households.Non-sampling errors.


HFCS: Assessment

• Strengths: Accurate data and no need for any assumption about

distributions. Policy relevant statistical profiles facilitate ‘hunger mapping’

and estimation of policy parameters like impact effectiveness of different policy options.

• Weakness: Problems of large scale data collection, processing and

timely dissemination. Even now periodic household income and consumption

surveys are not periodic; hence, at best it can be complementary to the FAO approach.


Anthropometric Measurements

• FAO & HFCS approaches are based on food consumption estimates at the household level.

• Anthropometric measures pertain to nutritional outcomes at the level of the individual.

• Results between these two approaches can differ since food consumption is only one of the factors that determine individual level nutritional outcome.

• Other factors: food losses, intra-household food distribution, individual health and activity levels.

• The two approaches measure different concepts but are complementary.



• Anthropometric measures: Broad range.• Most commonly used indicators: Relate to the

height and weight of individuals. • Anthropometric indicators differ between adults

and children since height does not change for the former.

• Consensus: On anthropometric indicators for children aged 0–5.



• Three most commonly used indicators – child stunting, wasting, and underweight.

• Offer insights into different dimensions of nutritional problems. Wasting (low weight for height): An indicator of acute undernutrition – relevant to monitor acute food shortages,

• Stunting (low height for age): An indicator of chronic undernutrition,

• Underweight (low weight for age): Summary indicator combining both facets.



• Data sources: Demographic and Health Surveys (DHS) and related Multiple Indicator Cluster Surveys (MICS).

• Standardized protocol to measure and weigh children; they are always based on national random samples, whereby sample sizes vary from around 3000 to over 100,000 children.

• Generally DHS and MICS cannot be merged with data from household consumption surveys – different samples by different organizations.



Advantages:• A direct measure of how undernutrition affects the health and

well-being of individuals – Because undernutrition that generates poor anthropometric

outcomes contributes to higher morbidity and mortality. • Three different child anthropometric indicators together indicate

both chronic and acute undernutrition. – Relief organizations use childhood anthropometry to monitor

the success of relief operations in emergency situations.• Estimates, as based on household survey data, permit (i) profiles

of undernutrition by groups and regions; and (ii) identify groups and localities particularly affected.



Advantages:• Survey data permit study of determinants and

hence, policy imperatives; facilitate design and monitoring of nutrition interventions.

• Facilitate monitoring of childhood anthropometry across space and time.



Problems:• Identification of the cause can be a problem since

poor anthropometry could be due to other factors.• DHS or MICS surveys are not periodic; hence useful

for medium term assessment and not for identifying short-term crises or annual monitoring.

• Permits focus on children only.



Problems:• Nutrition transition and implications.• Genetic differences in height and weight ; its

implications.

Food Security Statistics

http://www.fao.org/economic/ess/ess-fs/fs-data/ess-fadata/en/

Food Security Statistics 38

Food Security Statistics 39

40

Food Deprivation

• Prevalence of undernourishment in total population (percentage): Proportion of the population in a condition of undernourishment.


41

Food Deprivation

• Undernourishment: Undernourishment refers to the condition of people whose dietary energy consumption is continuously below a minimum dietary energy requirement for maintaining a healthy life and carrying out a light physical activity with an acceptable minimum body-weight for attained-height.



Food Deprivation

• Depth of hunger (intensity of food deprivation): The intensity of food deprivation indicates how much food-deprived people falls short, on average, of minimum food needs in terms of dietary energy. It is measured as the difference between the minimum dietary energy and the average dietary energy intake of the undernourished population (food-deprived). The intensity of food deprivation is low when it is less than 200 kilocalories per person per day and high when it is higher than 300 kilocalories per person per day. The greater the food deficit, the greater the susceptibility for health risks related to undernutrition.


Food Needs

Minimum Dietary Energy Requirement (kcal/person/day) • Most significant updates on undernourishment estimates are the

new standards for human energy requirements released in 2004 by FAO, WHO and UNU as well as the new standards of Body Mass Index released in 2006 by WHO.

• These new standards, used for the first time in SOFI 2008, affect the minimum dietary energy requirements (MDER) established by FAO. MDER is a crucial factor in FAO’s undernourishment methodology, as it establishes a cut-off point, or threshold, to estimate the prevalence (percentage) of the undernourished population in a country. When the threshold, or cut-off point changes, so does the prevalence of people estimated to be undernourished.


Food Needs

• Dietary energy requirements differ by gender and age, and for different levels of physical activity.

• Accordingly, minimum dietary energy requirements, the amount of energy needed for light activity and minimum acceptable weight for attained-height, vary by country, and from year to year depending on the gender and age structure of the population.

• For an entire population, the minimum energy requirement is the weighted average of the minimum energy requirements of the different gender-age groups in the population. It is expressed as kilocalories (kcal) per person per day.


Exercises

1. Assess the dimension of food insecurity in Bangladesh with reference to its macro and spatial dimensions and their policy imperatives.

2. How relevant are the policy questions discussed in the international context to Bangladesh today?

3. What are the advantages of Bangladesh as a small country in terms of policy formulation and implementation for food insecurity?

Thank You

Reference: Haen, Hartwig de, Stephen Klasen, and Matin Qaim (2011): “What do we really know? Metrics for food insecurity and undernutrition”, Food Policy, Vol. 36, No. , pp. 760-769.

Documents

Metrics for Food Security & Undernutrition