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To determine whether people are getting enough to eat requires the answers to two separate questions: what are people eating, and how much do they need? The former question is conceptually straightforward, but presents daunting data collection and estimation problems in practical terms. The latter compounds these problems. A diet that is adequate for some purposes is inadequate for others, since varying activity levels and patterns of growth can reconcile good health with a range of dietary intakes for the same individual. Thus, normative judgements as to desirable activity levels and growth patterns are implicit in any definition of dietary requirements. Uncertainties as to the range within which cost-free adaptation can occur and the factors underlying variation in requirements complicate the picture still further. Our review of hunger-estimation procedures that assess intake relative to need considers first the measurement of food availability and then the standards for need.
Food supplies
The discussion of estimates of food supply or dietary intake below is organized according to the three levels of social organization: these are the geographic region (in particular, the nation), the household, and the individual. Common approaches used to estimating food availability at each of these levels are described, with particular attention to measurement difficulties as well as sources of error and bias.
Food available to national populations
Estimates of national food supplies for most countries are maintained and regularly updated by the Food and Agriculture Organization (FAO) of the United Nations. These are based on food balance sheets, which involve detailed analyses of national food systems (see, e.g., FAO 1983,1984). The accuracy of these accounts has been extensively questioned. The FAO estimates of per capita, per day food availability for national populations are an essential part of any attempt at either assessing hunger globally or exploring its variation across countries.
These estimates are obtained by first calculating the amounts of specific foods available for human consumption within the country. This is done by taking the sum of amounts produced, imported, or withdrawn from carry-over stocks and then subtracting amounts lost in processing or transport, used for purposes other than human food consumption (seed, feed for animals, industrial raw materials), exported, or stored for later use. Estimates of the nutrient content (calories, protein, and fat) per unit of each food are then multiplied by the amount of the food available to obtain estimates of the total amounts of each nutrient available from each foodstuff. These are summed across all foodstuffs to obtain total supplies of each specific nutrient. The final step is to divide national totals by the number of days in the period to which the supply data apply, and by the total number of people in the population. Thus, the results are commonly expressed as per day, per capita nutrient availability.
The data requirements of the food balance sheets are enormous. Precise values are often lacking for at least some of the necessary inputs. In other cases the situation may be one of no data at all for certain parameters, rather than of imprecise data. To the extent necessary, the blanks are filled in with approximations, assumptions, and informed guesswork. The resulting estimates, therefore, should not be viewed as unduly precise.
According to the FAO (FAO 1984), statistics on non-food utilization of food supplies are perhaps most widely problematic, while estimates of loss between harvest and household typically rest on reliable local expert opinions. And "... even the production and trade statistics on which the accuracy of food balance sheets depends most are, in many cases, subject to improvement..." (FAO 1984: ix) Uncertainties on withdrawals from and deposits to carry-over stocks are limited by preparing food balance sheet estimates as three-year averages.
The degree of imprecision may be greatest for exactly that set of countries in which the aggregate food supply is likeliest to be short, since general statistical systems are less well developed in poorer and less-industrialized countries than elsewhere and even population data may be lacking. In 20 of the 125 counties covered in detail in the World Bank's World Development Report 1992 (World Bank 1992), the most recent census occurred in the 1970s or even earlier. Estimates of current populations extrapolated from past trends, or from old data that may have been inaccurate even when new, may be far from the truth. Nigeria's 1991 census, for example, counted a total of 88.5 million people, as compared with a UN estimate of 120.5 million people (APS 1992). Since dietary energy supply is divided by population to calculate per capita dietary energy supply, these alternative figures result in estimates that vary by 27.4 per cent. In this particular case, the food supply in Nigeria looks considerably more favourable when (presumably more accurate) data from the 1991 census are used instead of the older population estimates.
Food-production data may also be subject to extreme inaccuracies, especially in areas where much of the food produced is consumed directly by growers without ever entering the market. When such subsistence production occurs in remote regions it may be missed in national statistics. Even aerial surveys are likely to miss food production when it occurs as part of a system of shifting cultivation, with crops grown in small clearings in the jungle. Underestimation of available food is also particularly likely where uncultivated or lesser-known foods are commonly consumed. Some foods are omitted from food balance sheets entirely; in certain settings these may make up a significant portion of the total diet. Governments that tax and procure foods at below-market prices also present significant incentives for understatement of production by producers. These considerations will affect estimates of food production more in some areas than others, and therefore could bias the comparisons of relative food availability using food balance sheets. Svedberg (1991) has argued that the FAO's food balance sheet approach significantly underestimates food availability in sub-Saharan Africa relative to other regions. Despite their real shortcomings, however, food balance sheets provide the best information available as to national food supplies.
Household surveys
Surveys of representative samples of households are an alternative source for estimating national food supplies per capita. In addition, such surveys yield direct measures of household access to food. The FAO (1983) provides a useful comparison of several approaches.
Income/budget/expenditure surveys, with a broad focus on the economic situation of households, report amounts spent on food or the value of food consumed. Food quantities may be obtained as part of the process of estimating the value of food consumed, but are usually not shown in reports. This kind of survey omits food consumed outside the household and losses of food within the household; food gathered wild, received as a gift, and sometimes even produced by the household may also be omitted.
In contrast, food-consumption surveys focus more on amounts and nutrient composition of foods than on their economic value, and attempt to include food consumed away from home. Amounts may be ascertained by survey (recall), by consumption records maintained by the respondents, or by food weighing at meals (minus plate waste). Data collection (typically over a period of one to seven days for each household) is time-consuming and needs to be supervised for accuracy. Not surprisingly, food-consumption surveys of samples large enough, and sufficiently dispersed geographically, to yield national statistics are largely unavailable. India is the only country that conducts such surveys routinely. Nevertheless, this strategy is used more frequently in local-area studies and yields valuable information.
Finally, items typical of either income/budget/expenditure surveys or food-consumption surveys may be incorporated in multiple-purpose surveys. The information about intake from these is less detailed than that from studies focused on food and nutrition, but they significantly contribute to what is known about household food availability. One example is the Living Standards Measurement Survey that the World Bank has sponsored in a number of developing countries.
Despite their advantages, survey data of the types described above are flawed, as indicators of either national food supplies or the distribution of food across households, by the short time span to which they typically apply. Since household food consumption and food expenditure do vary over time, a household's apparent food security may be very much affected by the duration and/or the timing of data collection. Even from one day to the next, household food consumption and expenditure are often highly variable. As recognized in some methodological treatises (e.g. National Research Council 1986), this short-term variation suggests that the shorter the period covered, the more frequently extreme values of calories per capita per day will be found. Therefore, shorter-term data collection will tend to find higher proportions of households at extremely low (or high) levels of dietary adequacy. The sensitivity of proportions observed at the lower extreme to measurement duration matters when measuring hunger. Although statistical adjustments are possible (National Research Council 1986), this problem often goes unrecognized and therefore uncorrected.
Temporal variations in food intake will have different effects on survey results, depending on whether they have a common cause that affects households similarly or whether the causes are more household specific. If patterns of temporal variation in household food security are unrelated across households (for example, job loss for some families in the absence of recession or widespread lay-offs), surveys taken at different times might find different sets, but similar proportions, of households unable to meet the needs of their members, and food consumption or expenditure totalled or averaged across households might be unaffected. If many households experience the same temporal pattern of food security, however, even the proportion of households falling below any specified cut-off and the total of consumption or expenditure across households may be very much affected by the timing of data collection.
In subsistence agriculture, for instance, a food-consumption survey taken just before harvest might well show a dire situation indeed, but one a few weeks later a situation of abundance. Neither snapshot reasonably characterizes the population's usual access to food. Even the per day, per capita caloric availability over a three-year period reflected in a food balance sheet would not capture this situation; the more compelling reality for understanding who is hungry may be exactly the wide swings between scarcity and abundance rather than the level to which these two extremes average. Only longitudinal data can capture this reality. Enough evidence exists to suggest that temporal variation is an important dimension of hunger in some settings, but the research investment required to document such variation and its effect on the people who experience it leaves its details unexplored for most populations.
CONSUMPTION SURVEYS VERSUS SUPPLY METHODS. Overall, the consumption surveys versus supply methods of estimating national level food availability yield very different results. Comparing estimates of national per capita dietary energy supply based on income/budget/expenditure surveys and on food balance sheets, the FAO (1983) finds sizeable discrepancies. For developed countries, the survey results are consistently lower by hundreds of calories per day, at least partly owing to their omission of food consumed away from home. For developing countries, estimates from the two different sources also differ substantially, but the differences are smaller and not in a consistent direction. It is likely that the closer agreement of the two approaches for developing countries may reflect the fact that both surveys and food balance sheets underestimate food availability. Food balance sheets more accurately reflect availability in developed countries where most food is marketed than they do in developing countries. The more complete food balance sheet data for developed countries may eliminate a downward bias that would otherwise bring estimates into closer agreement with those based on income/budget/expenditure surveys.
In the FAO's assessment:
Annual food balance sheets tabulated regularly over a period of years will show the trend in the overall national food supply, disclose changes that may have taken place in the types of food consumed... and reveal the extent to which the food supply of the country, as a whole, is adequate in relation to nutritional requirements... (T)he food balance sheets... while often far from satisfactory in the proper statistical sense, provide an approximate picture of the overall food situation in the countries which may be used for economic and nutritional studies, the preparation of development plans, and the formulation of related projects. (FAO 1984)
Despite their difficulties, the food balance sheets are the best information we have to quantify national food supplies for most countries of the world. Because they are collected yearly, using the same methodology, they can provide valuable information on the relative magnitude of year-to-year fluctuations in food availability (Atwood 1991). Although shifts in production (especially shifts to marketed crops) may change the proportion of production recorded by the FAO even when total production remains unchanged, this type of change typically takes place over a number of years and is therefore unlikely to bias comparisons seriously between adjacent years.
Chapter 3 on food shortage in this volume draws on food balance sheets to assess the adequacy of national food supplies. They are also an essential input into global and regional estimates of numbers of people living in households that cannot afford the food their members need.
Food available to households
Even where the estimates of national per capita dietary energy supplies based on food balance sheets are quite accurate, they provide no clue about variable access to supply within nations. We know that some people go hungry, even in countries in which per capita total food supplies are far in excess of requirements, and that others are well fed, even in countries with too little food to meet the needs of their populations. We must have information on the distribution of food, not just the total amount available, in order to assess the prevalence of hunger. Surveys such as those discussed above provide one means of measuring variation across households in access to food.
With household-level food consumption or acquisition data, we can go beyond estimating the numbers of households, or of people in households, in food poverty. It is also possible to contrast the characteristics of households falling above or below some cut-off, or to compare access to food across different types of households. Both exercises help us to understand which households are hungry, not just how many. Household-level data also are indispensable for exploring associations between a household's food poverty status, health, education, and any other characteristics. Because nationally representative surveys gathering such information are scarce, our picture of household food poverty is necessarily incomplete. Many findings emerge from the literature on hunger and poverty; how widely these can be generalized is limited because there are so many settings for which the necessary data are not available.
A household's access to food is measured directly or estimated, and then compared with some standard of need to judge adequacy. The choice of cutoffs for minimally adequate food intake influences both the estimates of food poverty and the comparability across samples. The FAO and the World Bank now accept common standards, but the thresholds of undernutrition which they used even in the recent past were defined differently,1 and both organizations regularly readjusted their methodologies (Uvin 1994). Therefore, comparative estimates of food poverty across time or across data sources both need to check which methodology was being used, to standardize reporting.
Household food surveys are used to help to define what income levels are necessary for households to enjoy different levels of access to food. Income levels measured in other data sets then can be translated into access to food, to estimate the adequacy of the diet for households for which no actual food data were gathered. The widely cited estimates of world hunger produced by the World Bank and the FAO estimate indirectly the distributions of household income and proportions of households falling below food adequacy. These are calculated country by country but published only for regions, in the expectation that errors in single-country estimates will tend to balance out in aggregation.
Single-country estimates of numbers of people living in households that cannot afford to feed their members have been published by the United Nations Development Programme (UNDP 1992) for many countries. These rely on national reports of numbers in absolute poverty, defined as inability to meet their needs for food and other basic necessities. In some instances, figures are given separately for rural and urban areas, permitting within-population comparison of food poverty along at least this one dimension. Operational definitions of absolute poverty are country specific; the situations captured by these country-specific operationalizations are not comparable across countries without further standardization to adjust for different underlying conditions and methodologies.
Food available to individuals within households
DIRECT MEASURES. Ultimately, we measure the hunger of individuals, whose access to food is regulated by intra-household allocation rules and processes. We know that some individuals go hungry in households enjoying food security, while certain individuals are well nourished even in households that are food insecure overall. Solid conclusions regarding intra-household allocation of food require direct measurement of individual food consumption. This form of data collection is even more demanding in terms of time and skill than the household food-consumption survey. In addition to ascertaining and recording kinds and quantities of foods prepared for, and left over after, every meal, the researcher must also keep track of which household member gets how much of each dish. Collecting this kind of data within households is never unobtrusive: even if it is not resented, it may result in some change in the actual consumption, especially if those observed believe that their ordinary behaviour is subject to disapproval. Understandably, few surveys collect individual food-consumption data for a large or nationally representative sample of households over an extended period of time.
Even when the effort is made, differences in the completeness of dietary information across household members can still confound comparisons. Some are likelier than others to do some of their eating outside the household (food may be provided on the job or at school, or may be purchased from street vendors) and such meals or snacks tend to be underreported. Children also "forage" - a practice that has led some anthropologists to insist that "child following" is the only reliable method to record their intakes (Wilson 1974; Laderman 1991).
One particularly vexing instance of such differential completeness of dietary data relates to the difficulty of measuring amounts of breastmilk consumed by small children. Many food-consumption studies report only on children over 12 months of age, but intake of children past infancy will be underestimated where breast-feeding extends into toddlerhood, as it commonly does in developing countries.
Breastmilk is often completely omitted from studies on individual food consumption; this is hardly surprising, given that some manuals on food-consumption study methodology (e.g. Cameron and Van Staveren 1988) give no recommendations for estimating its intake. Jelliffe and Jelliffe (1989) outlined considerable problems in measuring breastmilk intake and concluded that all of the methods in use produced inaccurate estimates. Nevertheless, even large-scale surveys can question women as to how frequently their children nursed, rather than just whether they nursed. More labour-intensive surveys can observe women going about their daily tasks and count breast-feeding bouts over a full 24 hours.2 These methods could provide a better indication of how important breastmilk is in the diet of children in different cultures. An indication - rather than a precise measurement - is all that is going to be available from dietary-survey data. More accurate methods, such as isotope dilution of labelled water, are too costly to be used in large-scale surveys.
The frequent omission of breastmilk from food-consumption data may qualify the common finding that the youngest are worst fed. While there are undoubtedly times and places in which children do receive less than a fair share of household food supplies, the downwards bias on estimates of food consumption for the youngest, resulting from omission of mother's milk, may both exaggerate such a pattern where it exists and create one where it does not.
INDIRECT MEASURES. The difficulty of collecting data on individual food consumption has led some researchers to use less-direct measures. For example, the order in which different household members are served at meals often is interpreted as an indicator of relative access to the common food supply, and the conclusion is drawn that those served last receive less than a fair share (e.g. den Hartog 1973; Katona-Apte 1975; Maher 1981; Papanek 1990).
Reports that certain foods are normatively forbidden to, or reserved for, people in particular age, gender, or status categories provide a second set of indicators of within-household differences in access to food and the relative adequacy of diets. These observations suggest differences in dietary adequacy within a household. However, without further measurement of actual intakes compared with some nutritional standard they are not conclusive. More effort has to be made to validate these kinds of intra-household consumption indicators; where individual food-consumption data are available, it would be useful to explore the extent to which inferences that could be drawn from eating order and other aspects of dietary tradition are borne out.
Nutritional requirements
Measures of food supply available to national populations, accessible to households, or consumed by individuals always must be compared with amounts required, in order to permit any conclusion as to adequacy. Our discussion of nutritional requirements, that here focuses on energy, covers the same three levels of social organization as the preceding discussion of food availability; however, because the requirements for larger aggregations of people are conceptually based on the sum of individual requirements, we proceed from the individual, to the household, to the population.
Individual requirements
According to the United Nations:
The energy requirement of an individual is the level of energy intake from food that will balance energy expenditure when the individual has a body size and composition, and level of physical activity, consistent with long-term good health; and that will allow for the maintenance of economically necessary and socially desirable physical activity. In children and pregnant or lactating women, the energy requirement includes the energy needs associated with the deposition of tissue or the secretion of milk at rates consistent with good health. (WHO 1985: 12)
These requirements vary across individuals and within individuals over time. They are influenced by gender, body size, physical activity level, age, reproductive status, and disease. In addition, cross-population variation unexplained by these factors appears to reflect some influence of climate as well as other factors, such as dietary composition. But individuals who appear comparable on all these dimensions and who are in energy balance, as indicated by absence of weight loss or gain, still vary widely in their caloric intake. Consequently, accurate determination of an individual's caloric requirements would necessitate very intensive data collection under laboratory conditions. This is clearly infeasible on any large scale. Thus, studies of individual dietary adequacy most commonly compare actual intake with expected or average per capita requirements for persons similarly classified on the same background variables.
The most contentious and difficult aspect of caloric requirements relates to adaptations to a constrained diet. Desirable patterns of growth for children and desirable patterns of physical activity at all ages are an important part of this controversy. Some analysts (e.g. Sukhatme 1988) have argued that intake and expenditure of dietary energy function as a self-regulating homoeostatic system in which the efficiency of energy use is increased as intake decreases and decreased as intake increases. The argument is a rather technical one, but its real-world implications are far from trivial. It has been taken as demonstrating "cost-free" adaptation to low intake - the possibility of maintaining not only energy balance and health but even usual activity levels on severely restricted consumption.3
Others have responded (see, e.g., Scrimshaw and Young 1989; Waterlow 1989) that adaptation to low intakes does not occur without undesirable limitation of physical activity. A proportion of the reduction in energy use that occurs as a result of reduced intake is apparently innocuous: weight loss itself causes some decline in caloric requirements, and less energy is used in digestion, absorption, and storage of nutrients when less food is consumed. However, the major mechanisms for reduced energy expenditure are behavioural. Therefore, most nutritionists do not view the adaptation to low intakes as cost free.
Although controversial, the concept of cost-free adaptation may well underlie decisions by some major nutrition-monitoring organizations (e.g. FAO 1977, 1985; NNMB 1981) to define cut-offs for undesirably low caloric intake at levels two standard deviations below average requirements. Setting such low cut-offs for minimal intake guarantees that the prevalence of hunger will not be overestimated. But unless the people with the lowest intakes also have the lowest requirements, it also guarantees that a high proportion of cases of genuinely inadequate intake will go unrecognized.
The controversy about the degree of adaptation to nutritional stress is also a policy debate about resource allocation. Few would argue that adaptation to extreme deprivation could be cost free, but those who interpret adaptation to lower levels of nutritional stress as cost free favour allocating resources to more narrowly focused nutritional programmes that would benefit only those in extreme need. If their premise is correct, this would reduce expenditure while increasing effectiveness. Those who have higher estimates of the costs of more moderate deprivation emphasize the needs of marginally nourished people. Their arguments tend to focus on the difficulty of emerging from poverty when productivity is limited by intake (e.g. Dasgupta and Ray 1990). If this is the case, government expenditure on broader nutrition programmes represents a better long-term policy choice, since it will improve both national productivity and national income distribution.
Household requirements
To estimate requirements for aggregations of individuals, whether these be households or national populations, it is necessary to consider what kinds of individuals make them up. Households are commonly defined - even outside the literature on hunger - as groups of individuals who share cooking facilities. Some individuals have regular access to food in more than one household (e.g. polygynous men whose wives do not cook together), and this complicates the estimation of household need.
Household need is determined by the number of members as well as their age, gender, and other determinants of individual need listed above. For households, caloric requirements are often estimated as the product of household size and national average per capita requirements. The implicit assumption is that each household's composition mirrors that of the nation as a whole. In fact, of course, households differ in their composition: the nutritional needs of a woman living with three children under five differ substantially from those of a childless couple living with two of the husband's brothers. Although estimates of household requirements reflecting each household's own composition are preferable in principle, detailed analysis of Indonesian data (see table 2.1) suggest that the additional analytical effort involved makes little difference to the proportions of households estimated to consume less than they need. Approximately equal numbers of households are misclassified in each direction by relying on national average per capita requirements. Thus, although misclassification does occur for many households, aggregate results are virtually unaffected, at least for this population.
Table 2.1 Percentage of households in food poverty by definition of household caloric requirements, Indonesia, 1980
| Household requirements defined by product of household size and national per capita requirement | ||||
| Households below cut-off | Households above cut-off | Total | ||
| Household requirements defined as sum of individual requirements | Households below cut-off | 47.26 | 5.62 | 52.88 |
| Households above cut-off | 5.29 | 41.83 | 47.12 | |
| Total | 52.55 | 47.45 | 100.00 | |
Source: Data from the Indonesian National Socio-Economic Survey
of 1980; tabulation by Mark M. Pitt.
Caloric consumption requirements for households are the sum of the requirements of their individual members. However, if requirements are to be compared with measures of food supplies available to a household, rather than with those actually eaten within it, some allowance should be made for loss or wastage of food within the household. Such losses occur, for example, owing to spoilage, to infestation by insects or other pests, to losses in preparation, or to "plate waste" - leftovers discarded. While plate waste may be low in situations of scarcity, poor storage facilities make it difficult to avoid other forms of food loss within the household. More-affluent households may have the storage facilities needed to minimize spoilage but are less likely to make sure every bit of edible food is consumed.
Thus, for different reasons, some loss of food is expected in both poorer and wealthier households.
National requirements
Determining caloric need for national populations is somewhat less complicated, because the fluidity of boundaries between households is not an issue and the gender and age composition of national populations is generally well known. Estimates of average per capita caloric requirements for national populations incorporate information on typical body sizes and physical activity levels, as well as age and sex composition, and may also allow for effects of childhood disease and desired growth patterns for children.
Several sets of average per capita caloric-requirements estimates for national populations have been published by various organizations and applied widely. Unfortunately, requirements estimates for the same population may vary substantially. More unfortunately still, some statistical compendia present caloric availability data only as a proportion of requirements, without specifying what standards for requirements are being used. Thus, the potential for confusion and contradiction is substantial. The remainder of this section briefly reviews some of the reasons for the differences in sets of requirements estimates.
Estimates of national average per capita caloric requirements produced by the FAO were published in the Fourth World Food Survey (FAO 1977) and have been used since in preparation of several kinds of national-level estimates of hunger. FAO publications from 1990 (e.g. FAO 1990a, 1990b, 1990c), however, show a different set of caloric-requirements estimates, in most cases substantially lower than the old ones.
The difference between these sets of estimates - a median decrease of 280 calories per day - was enough to result in drastically different pictures of world hunger. For example, the total 1987 population of countries with per capita caloric availability below requirements was 1,603 million relative to the old requirements, but 152 million relative to the new ones (Millman and Chen 1991). The difference turns out to be attributable to two main factors. First, the new estimates incorporate new (and presumably more accurate) data on body sizes of national populations. In most cases, this new information contributed to a reduction in requirements estimates. Second, and more significant, the reduced FAO caloric-requirements estimates eliminate an allowance for food losses within the household or retail establishment. The FAO's food balance sheets do account for losses of food prior to harvest and during food storage, processing, and delivery to retail establishments, but they no longer allow for losses within households or institutions. In the past, their caloric requirements estimates were inflated by 10 percent to allow for such losses.
Not accounting for food loss within households amounts to making the unrealistic assumption that its value is zero. Some allowance would seem essential in assessing the adequacy of supplies of food available to households or to national populations. Comparisons of hunger prevalence at different points in time should not be made without attention to the standards applied, or misleading conclusions as to trend may result. Comparisons made using data published since 1992 are less problematic because the FAO and the World Bank have adopted a common methodology for producing their estimates.
The balance of food supply and requirements
At each level of social organization that we consider, conclusions about hunger are seriously affected by the measurement issues raised in this chapter. We draw attention to the methodological difficulties in the study of hunger, not to create pessimism about our ability to measure hunger but to inform comparisons between results derived from different practices. Assessments of food shortage may underestimate production and underestimate waste, but, as we have emphasized, the most commonly used methods are likely to yield reliable data about trends in food security. Employing even faulty methodologies consistently gives us a picture of how the balance of food supply and requirements is changing, and can even help identify what factors are influencing the changes.
Assessments of food poverty may be flawed by lack of attention to household composition or the changeable nature of household boundaries, but we have shown that these issues are unlikely to affect estimated levels of food poverty profoundly. In chapter 5 we will address how these and other issues affect our understanding of which households are in food poverty.
Comparisons across countries, of the extent of food poverty or the determinants of food poverty, may be flawed or reach varying conclusions if they fail to account for different types of data and definitions employed within countries. Studies that measure household food availability by documenting consumption cannot be directly compared with those that estimate food poverty on the basis of low income. But important insights into the determinants of hunger can result from comparing methodologies and outcomes in a single setting that can then guide additional research. If household income seems to be adequate and household food consumption is unacceptably low, the determinants of spending patterns then deserve more attention than the determinants of income. If certain households seem to do a better job than others, of balancing intake with requirements despite income constraints, then focusing on nutritional strategies and sources of food and income in those households might be productive.
Assessments of food deprivation based on intake must be careful to consider individual requirements when drawing conclusions, especially where judgements of discrimination leading to inadequate intake are involved. Some studies of intra-household food allocation have concluded that women and children received less than their fair share because they consumed fewer calories per day than others. If everybody had the same caloric requirements, differences in consumption could, indeed, be interpreted as showing patterns of advantage and disadvantage. But caloric requirements do vary and, typically, are lower for women and children than for others. To reach meaningful conclusions on adequacy or equity, dietary comparisons must examine individual intake relative to individual need. This can be done by dividing each household member's consumption by the corresponding estimate of requirements and comparing the results, often referred to as indices of dietary adequacy or caloric adequacy, which can be interpreted to show patterns of discrimination or equity. Only where the ratio of consumption to requirements is lower for women than for men, and for children than their elders, can we then conclude that women and children are at a disadvantage in the intrahousehold allocation of food. The additional complication of gender bias built into standards is discussed further in the section on choice of standards.
Another set of studies bases conclusions about discriminatory allocation of food within the household on the observation that certain household members are eating less than they need, without demonstrating that others are doing any better. In these instances, we usually have solid evidence of inadequate diets for those identified as victims. Again, however, a comparison with the situation of others is necessary to support a conclusion of relative disadvantage: other household members may be equally underfed, and, if so, our interpretation of the situation should be quite different from that if we find that others in the same household consume a more adequate diet. If all are underfed, the household is clearly in food poverty and food deprivation is being experienced by all its members. If only some are food deprived, this may or may not result from food poverty.