Chronic Energy Deficiency : Consequences and Related Issues (International Dietary Energy Consultative Group - IDECG, 1987, 201 pages): Methodology of field studies related to socioeconomic effects of chronic energy deficiency: 4. Human capital studies: 4.1. Methodological aspects

Chronic Energy Deficiency : Consequences and Related Issues (International Dietary Energy Consultative Group - IDECG, 1987, 201 pages)

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Introduction

Research relating to energy adaptation in man

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1. General introduction

2. The Sukhatme-Margen hypothesis

3. Is energy balance regulated in man?

4. The time basis of energy regulation

5. Altered metabolic rate

6. Other Sukhatme analyses

7. Problems in testing the Sukhatme-Margen hypothesis

8. The reproducibility of metabolic rates in man

9. Adaptation to underfeeding

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9.1. The range of adaptation

9.2. The response to semistarvation

10. Overfeeding studies

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10.1. Early studies

10.2. Prolonged overfeeding

11. Attempts to test the Sukhatme-Margen hypothesis(es)

12. Concluding remarks

References

Seasonality in energy metabolism

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1. Introduction

2. Reasons of seasonal variations in energy metabolism

3. Seasonal body weight fluctuations

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3.1. Children

3.2. Adults

4. Seasonal fluctuations of energy expenditure

4.1. Basal metabolic rate (BMR)

4.2. Physical activity and energy expenditure

5. Conclusions

6. Research priorities

References

Chronic energy deficiency and the effects of energy supplementation

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1. Introduction

2. Definitions and descriptions

2.1. Chronic energy deficiency

2.2. Energy supplementation

2.3. Targets of supplementation

2.4. The effects of supplementation

3. Approaches to the study of the effects of energy supplementation

4. Supplementation studies

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4.1. The INCAP study

4.2. The Gambian studies

4.3. The Bacon Chow Study, Taiwan

4.4. Conclusions

5. Some possible explanations for the small effects

5.1. Are the recipients really malnourished?

5.2. Are the target groups being energy-supplemented?

5.3. Are the target groups appropriate?

5.4. Are the outcome variables appropriate?

6. Contemporary models

7. Gaps in our knowledge

8. Concluding comments

References

A critical view of three decades of research on the effects of chronic energy malnutrition on behavioral development

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1. Background

2. The main-effect model

3. Deficiencies of the main-effect model

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3.1. Outcomes of primary and secondary malnutrition

3.2. Effects of the environment and experience

3.3. Outcomes of monofocal and multifocal interventions

4. Suggestions for future research

References

Effects of chronic energy deficiency on stature, work capacity and productivity

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1. Studies in adults

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1.1. Malnutrition and VO2 max

1.2. Endurance

1.3. Productivity and physical work capacity

2. Studies in children

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2.1. Anthropometry, sexual maturation and body composition in boys

2.2. Growth of work capacity

3. Men and boys

3.1. Body size, composition and VO2 max

3.2. Energy cost of load-carrying

3.3. Efficiency of economy of submaximal work in malnutrition

3.4. Reduced physical activity in chronic energy deficiency

3.5. Work performance in large and small individuals

4. Productivity, earning and nutrition in developing countries

5. Summary

Acknowledgements

References

The energy requirements of pregnancy and lactation

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1. Introduction

2. Background

3. Methodology

3.1. Selection of subjects

3.2. Body weight and body fat

3.3. Energy intake

3.4. Basal metabolic rate (BMR)

3.5. Standardized exercise test

3.6. Normal daily activity pattern

3.7. Daily energy expenditure

3.8. Frequency of measurements

4. Results and discussion

5. Conclusion on pregnancy data

6. Lactation

References

Methodology of field studies related to socioeconomic effects of chronic energy deficiency

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1. Introduction

2. Conceptual framework

3. Study designs

4. Human capital studies

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4.1. Methodological aspects

4.2. Analytical limitations

5. Economic behavioral studies

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5.1. Methodological aspects

5.2. Analytical limitations

6. Participation of the community in research

7. Concluding remarks

Appendix

References

Pregnancy, lactation and childhood: Report of working group 1*

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1. Introduction

2. Pregnancy

2.1. New information

2.2. Policy implications

2.3. Needs for research

3. Lactation

3.1. New information

3.2. Policy implications

3.3. Needs for research

4. Children

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4.1. Energy supply and physical growth of infants and children

4.2. Energy supply and physical activity of children

4.3. Chronic energy deficiency and development

4.4. Causes of inadequate energy intakes in children

5. Conclusion

Work capacity, work performance: Report of working group 2*

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1. Definitions

1.1. Physical work capacity

1.2. Work performance

1.3. Chronic energy deficiency (CED)

2. Summary of existing knowledge

3. Priority studies

4. Relationship of the proposed research activities to developing countries

5. Recommendations for continuing obligations

References

Social and economic development: Report of working group 3*

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1. Introduction

2. Designs for studying the effects of low energy intake on behavior

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2.1. Naturalistic designs

2.2. Experimental designs

3. Types of variables

4. Proposed future activities with IDECG support

List of participants

4.1. Methodological aspects

Certain methodological aspects of human capital studies have been summarized in Table 1. These studies in the past have mainly employed a cross-sectional design, using as the experimental variable the variation in nutritional status encountered in the study subjects. Body composition indicators or daily energy intakes have been used to represent levels of chronic energy deficiency.

The few relevant studies which are available have used economically active adults as subjects within a homogeneous occupational group. In one case, a parameter of childhood nutrition (adult stature) was associated with adult productivity in order to quantify human capital formation via nutritional investment during childhood (IMMINK et al., 1984). In another study, it was demonstrated that in a cohort of children protein-energy intake levels were related to their mental development. In a cohort of adult workers from the same social stratum as the cohort of children, mental development was related to productivity (SELOWSKY and TAYLOR, 1973). The general conclusion of the study was that undernutrition in children represents disinvestment in human capital.

Alternative key economic indicators which can be used for the analysis are (a) total income from all productive activities, including the imputed market value of home production activities; (b) total earnings, in wage employment, or (c) number of work units performed and valued at market wage rates. The first indicator is preferable though costly in terms of data requirements. Direct questions regarding income earned usually result in a systematic under-reporting¹.

1 This may not be serious it the reporting bias is a constant proportion of true income, but this is usually not the case.

Alternatively, as a proxy of earned income, total expenditures (plus net changes in savings if relevant) are often used.

Longitudinal studies which involve an induced change in nutritional status, either by means of supplementation or naturally occurring change in energy availability, offer an opportunity to undertake internal rate-of-return analysis, assuming that the measurement period is sufficiently long to measure the full impact on productivity. Relevant supplementation studies (see section 3) did not demonstrate any significant productivity effect during the measurement periods. To the author's knowledge no human capital analysis has been applied in longitudinal CED studies.