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Food insecurity is a complex phenomenon attributable to a range of temporally and spatially varying factors, such as the socio-economic and political environment, the performance of the food economy and the health and sanitation situation (FIVIMS, 2003). Food-insecure people are those whose food intake falls below their minimum energetic requirements. They are also those who exhibit physical symptoms caused by energy and nutrient deficiencies resulting from an inadequate or unbalanced diet or from the body’s inability to use food effectively because of infection, disease or poor sanitation (DFID, 2003; FIVIMS, 2003). In addition to the numerous physical and psychological costs associated with food insecurity there are a number of economic costs, such as the costs of lost productivity or additional health care (Chung et al., 1997). Attempting to ensure food security can be seen as an investment in human capital. A properly fed, healthy and active population contributes more effectively to economic development than one which is physically and mentally weakened by an inadequate diet and poor health (World Bank, 1986).

The definition of food insecurity encompasses many elements and therefore no single indicator can measure its prevalence or extent. Five main types of method are currently used for assessing the extent of hunger and malnutrition, each with different applications, advantages and disadvantages. Qualitative methods assess the perceptions of hunger and behavioural responses while also measuring the stability of supply (FIVIMS, 2002). The FAO method estimates dietary intake and its relation to energy needs thus providing an indication of the availability of food supply (FSIEWS, 2001). The individual dietary survey and the household income and expenditure survey methods measure access to food supplies (Ferro-Luzzi, 2002; Smith, 2002). Finally, anthropometry determines the physical effects of malnutrition on growth and thinness thus indicating the extent of the biological utilization of food (Gibson, 1990; Cogill 2003). These methods assess the effects of hunger on health, suffering, behaviour and economics and are compared in Table 1 and outlined below.

4.1 Qualitative method

The qualitative method of assessing food security examines people’s perceptions about energy inadequacy and food deprivation and provides a simple, direct measure of food insecurity and hunger that is country- and context-specific (Kennedy, 2002). The method targets those who have experienced food insecure conditions directly and examines experiential dimensions including emotional effects and behavioural changes (FIVIMS, 2002). Interviewers look for evidence of an alteration in food type consumption through substitution for cheaper foods, the physical sensation of hunger or weight loss, the experience of running out of food without money to obtain more and the perception that consumed food was inadequate in quality or quantity (Bickel et al., 2000). This method has mostly been used in developed countries, although efforts are under way to extend its use to developing countries (FIVIMS, 2002). It could easily be adapted to looking at the introduction of aquaculture and the consequent impact on food security. Nevertheless, due to the highly context-specific and linguistically dependent nature of qualitative methods it may never be possible to develop a universal measure to capture the successive stages of severity in food insecurity across diverse regions and peoples (Kennedy, 2002).

4.2 FAO method

The FAO method for measuring food deprivation is based on a comparison of energy requirement norms with usual food consumption, expressed in terms of dietary energy (see Box 2). A minimum amount of dietary energy intake is essential to maintain body weight and so the individual energy requirement is defined as the level of energy intake from food that will balance energy expenditure when an individual has a body size, composition and level of physical activity consistent with long-term good health (Naiken, 2002). The FAO method measures the distribution of dietary energy consumption on a per person basis from the daily dietary energy supply (DES) per caput for a country, which is derived from food balance sheets, averaged over three years. DES therefore relates food availability to a theoretical energy allowance, which varies between 2 000 and 2 350 kcal/day/person depending on the age, sex, health status and physical activity of the individual (FSIEWS, 2001). National DES gives a good indication of the extent of poverty (Mason, 2002) and those countries with food supply problems (Naiken, 2002).

The per caput DES refers to food acquired by households rather than the actual food intake of individual household members (Naiken, 2002) and it therefore does not show the inequitable distribution of available supplies within countries. This method may overstate prevalence of undernourishment in some regions and understate it in others by placing too much stress on mean energy consumption and not enough on energy distribution (FIVIMS, 2002). In addition, there are serious inaccuracies in the food balance sheet data arising from flawed production and trade data in countries with relaxed borders and thus may provide an unreliable indicator of the scope of the undernutrition problem (Svedberg, 1999; FIVIMS, 2002).

Box 2: FAO method calculations

The basal metabolic rate (BMR) is the energy expended for the functioning of an individual in a state of complete rest and is derived from the Schofield equations, a set of sex-age-specific regression equations based on body weight. The total energy expenditure of an individual can be expressed as multiples of the predicted basal metabolic rate BMR. This ratio of the total energy expended to the BMR has been termed the physical activity level (PAL) index and reflects both the body weight and the level of physical activity of the individual (Shetty and James, 1994). A PAL value of 1.4 corresponds to the maintenance requirement, which is the minimum level of energy expenditure compatible with health, and so a value of 1.4 times the BMR may be used as a cut-off point for assessing the prevalence of chronic energy deficiency (Shetty and James, 1994). The body mass index is used to determine the height to weight relationship and by exposing underweight individuals gives an indication of the extent of food insecurity in a population. The body mass index (BMI) can be used as a reflection of the body energy stores and is calculated as:

Individuals with a BMI >18.5 are considered to have adequate energy reserves, as are those with a BMI between 17 and 18.5 and a PAL >1.4. However those with a PAL index value <1.4 may be suffering from chronic energy deficiency (Shetty and James, 1994).

4.3 Individual dietary survey methods

Individual dietary survey methods measure actual food intake at the individual level by taking a dietary history, administering a food frequency questionnaire, recording weights of foods consumed, asking respondents to recall what they ate in the previous 24 hours or analysing the chemical and nutrient content of diets (Wiehl and Reed, 1960; Ferro-Luzzi, 2002). This information is then compared with dietary energy requirements to determine the proportion of the population with deficient energy intakes (FIVIMS, 2002). The methods are flexible and can be adapted to fit the purpose of the study. Individual intake surveys therefore assess food patterns, provide estimates of intake of particular foods and are the only existing method to reveal intra-household distribution of food (FIVIMS, 2002). In addition to providing data on energy availability, food intake surveys give estimates of micronutrient intakes (Mason, 2002).

One unique strength of the individual dietary survey method is that the results can be validated using the doubly labelled water method which measures energy expenditure (Ferro-Luzzi, 2002). Large-scale individual dietary intake surveys may not be the best way to monitor trends of food security over time because of the associated costs and logistical difficulties (Ferro-Luzzi, 2002), and so this technique may be a useful validation tool for other food security measurement approaches that are routinely used. Constraints encountered in conducting a dietary survey in developing countries include cultural reluctance to allow strangers to handle foods destined for home consumption, local taboos or rules that cause embarrassment and limit cooperation, and the culturally specific ways of purchasing, storing and cooking food (Kigutha, 1997). Some studies have shown that fat and carbohydrate intakes are under-reported to a larger extent than protein (FIVIMS, 2002), while fish and other non-staple foods consumed in small quantities may be missed in surveys, leading to an underestimate of levels of micronutrient intake (Mason, 2002). Indeed under-reporting is common in dietary assessment surveys causing a potentially significant source of error.

4.4 Household income and expenditure surveys

Food insecurity is increasingly concentrated in particular regions or groups within countries and thus there is a great need for sub-national information. Household income and expenditure surveys (HIES) obtain information on a variety of specific conditions, experiences and behaviours indicating the severity of the condition (FIVIMS, 2002). The set of food security questions (see Box 3) can be combined into a single overall measure called the food security scale which is a continuous, linear scale measuring the degree of severity of food insecurity experienced by a household. The statistical procedure depends on the number of affirmative responses to the increasingly severe sequence of survey questions which examine three key measures of food insecurity (Smith, 2002):

The household food energy deficiency measure indicates whether a household falls below a certain energy intake requirement by comparing energy availability with a requirement based on age and sex composition (Smith, 2002). The depth of energy deficiency can therefore also be determined.

Dietary diversity, the number of different foods or food groups consumed by a household, is considered to be a good summary measure of diet quality (Hoddinott and Yohannes, 2002). The quality of food is a complex characteristic that determines its safety, nutritional value, acceptability to the consumer and functional properties (FSIEWS, 2001). There is some debate as to whether dietary diversity can be considered as an indicator of food security rather than just dietary quality, but recent work has shown that increased dietary diversity is associated with increased birth weight, child anthropometric status and haemoglobin concentrations (Allen et al., 1991; Bhargava, Bounis and Scrimshaw, 2001; Rao et al., 2001).

The percentage of a household’s total expenditure on food gives an indication of their vulnerability to food insecurity in the future. In the case of a job loss, natural disaster, disease onset or price policy reform, a household will be particularly at risk if over 70 percent of their income is spent on food (Smith, 2002).

Household income and expenditure surveys (HIES) are a source of policy relevant measures allowing monitoring and targeting of regional or national prevalence of food insecurity. However data collection and computation costs are high in terms of time, financial resources and technical skill required and cannot determine inequalities of access to food between individuals within a household (Smith, 2002). The household is only examined at the time of interview so changes may well occur, and estimates may be biased through systematic non- sampling errors. In addition, social desirability problems may occur when respondents do not want to look bad in front of interviewers (FIVIMS, 2002).

Box 3: Specimen core food security module where all questions below are answered: often true, sometimes true, never true or don’t know/refused.

1. I worried whether my food would run out before I got money to buy more.

2. The food that I bought just didn’t last and I didn’t have money to get more.

3. I couldn’t afford to eat balanced meals.

4. I relied on only a few kinds of low-cost food to feed the children because I was running out of money to buy food.

5. I couldn’t feed my children a balanced meal because I couldn’t afford that.

6. My children were not eating enough because I just couldn’t afford enough food.

7. In the last 12 months, since last (name of current month), did you ever cut the size of your meals or skip meals because there wasn’t enough money for food?

8. How often did this happen - almost every month, some months but not every month, or in only one or two months?

9. In the last 12 months, did you ever eat less than you felt you should because there wasn’t enough money to buy food?

10. In the last 12 months, were you very hungry but didn’t eat because you couldn’t afford enough food?

11. In the last 12 months, did you lose weight because you didn’t have enough money for food?

If affirmative response to any one of these questions, continue, otherwise skip to end.

12. In the last 12 months did you ever not eat for a whole day because there wasn’t enough money for food?

If affirmative response to above:

13. How often did this happen - almost every month, some months but not every month, or in only one or two months?

If there are children under 18 years old in the household, ask the next questions, otherwise skip to end.

14. The next questions are about children living in the household who are under 18 years old. In the last 12 months, since (current month) of last year, did you ever cut the size of your child’s meals because there wasn’t enough money for food?

15. In the last 12 months did (child’s name) ever skip meals because there wasn’t enough money for food?

If affirmative response to above

16. How often did this happen- almost every month, some months but not every month, or in only one or two months?

17. In the last 12 months, was your child ever hungry but you just couldn’t afford more food?

18. In the last 12 months, did your child ever not eat for a whole day because there wasn’t enough money for food?

Table 1: Current methods for assessing food insecurity


Main indicator(s)

Data acquisition

Level of indicator

Potential problems




Percentage reporting experience of food insecurity and hunger.

Interviews looking for perceptions of energy inadequacy.

Individual, population subgroups and national.

Analysis does not include information on prices and quantities in markets or the functioning of the transport system. Perception of deprivation is influenced by person’s relative position in society.

Quick to administer, well understood by policy-makers and specific to country and context.

Bickel et al. 2000;
Kennedy 2002;
Mason 2002.


Comparison of energy requirement norms with usual food consumption, expressed in terms of daily dietary energy supply (DES).

DES per capita for a country, derived from food balance sheets.


Roots and tubers are not included in food balance sheets, which may also have flawed production and trade data. Only energy intakes are considered, but not that of micronutrients.

DES gives good indication of where individuals are suffering and correlates with income to indicate extent of poverty.

Svedburg 1999;
FIVIMS 2002;
Mason 2002;
Naiken 2002.

Individual dietary survey

Individual intake related to requirement.

Dietary history, food frequency questionnaire, record of food consumed, chemical and nutrient analyses.

Individuals or population subgroups.

Activity levels are largely unknown for assessing requirements and potential cultural constraints where strangers handle food. Fat and carbohydrate may be underreported while micronutrients are missed.

Flexible, reveals intra-household distribution of food and estimates micronutrient intake. Results can be validated with doubly-labelled water technique.

Kigutha 1997;
FIVIMS 2002;
Mason 2002.

Household income & expenditure survey

Depth of deficiency, dietary diversity and percentage of household’s total expenditure on food.

Food security questions combined into overall scale.

Population subgroups or national.

Often fails to determine accurate account of food eaten outside home. Data collection and computation costs high and households may change after interview.

Valid, policy relevant, multilevel measure.

Hoddinott &
Yohannes 2002;
Smith 2002.


Percentage of underweight or stunted children; adults with low body mass index (BMI).

Human body measurements compared with international reference standards.

National or population subgroups.

Children’s ages must be accurately reported. Poor results may reflect past history of undernutrition rather than current problem. Risk of food insecurity may still be high and temporal changes not indicated.

Simple, non- invasive, precise method that can be carried out by relatively unskilled personnel using inexpensive equipment.

Gibson 1990;
Maxwell & Frankenberger 1992;
FIVIMS 2002;
Cogill 2003.

4.5 Anthropometry

Anthropometry is the use of human body measurements to obtain information about nutritional status. It is a simple, safe and non-invasive procedure giving precise quantification of the degree of undernutrition (Gibson, 1990). Nationally representative anthropometric surveys have now been carried out for most developing countries which allow estimates to be made of the proportion of the population lying below established cut-offs and who are therefore considered to be undernourished (FIVIMS, 2002). Undernutition is diagnosed when individuals’ anthropometric measurements in terms of weight and height fall below international reference standards (Cogill, 2003). Anthropometric indicators used for assessing the nutritional status of children now have a degree of international acceptance but due to the varying effect of puberty there are currently no accepted indicators for undernutrition in adolescents. The status of adults is determined using the body mass index (see Box 2) thus indicating the extent of food insecurity in a population by exposing underweight individuals. Those individuals with a BMI <18.5 are considered to have inadequate energy reserves which, evidence suggests, increases morbidity and mortality, decreases work productivity and lowers birth weight in offspring (FIVIMS, 2002). Poor growth in children as well as underweight in adults may be the consequence of both inadequate food intake and poor absorption of food caused by environmental factors such as infections which can lead to the impairment of physical and cognitive functions (Shetty, 2002).

Information is generated on past nutritional history and relatively unskilled personnel can perform measurement procedures using inexpensive equipment. The methods used are therefore suitable for large, representative population samples and can be used to monitor and evaluate changes in nutritional status over time (Gibson, 1990). Country trends are particularly useful for determining the rate and slope of progress or regress and anthropometry can also be used to track individual status, for example monitoring a child’s weight over time is a powerful tool to look at the impact of introducing a new crop or technology such as aquaculture (FIVIMS, 2002). However, there is some debate as to whether undernutrition is an adequate measure of food insecurity as poor anthropometric results, especially stunting, reflect a past history of undernutrition rather than a current problem (FSIEWS, 2001). Anthropometric indicators are status indicators and therefore do not indicate changes in the nutritional status of population or the most vulnerable groups. In addition, acceptable anthropometric results do not necessarily demonstrate adequate food security as risk levels may be high (Maxwell and Frankenberger, 1992).

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