Initial efforts by health professionals to reduce FM involved endurance exercise protocols mainly because of the large impact on total energy expenditure and links to coronary heart disease risk amelioration. More recent efforts using resistance exercise training, or combinations of resistance and endurance exercises, have been tried to maintain the interest of participants as well as to positively affect body composition through stimulation of anabolic stimuli (Grund et al., 2001). Practitioners of speed, power, and resistance exercises can change body composition by means of the muscle-building effects of such exertions. Moreover, exercises that strengthen muscles, bones, and joints stimulate muscle and skeletal development in children, as well as assist in balance and locomotion in the elderly, thereby minimizing the incidence of falls and associated complications of trauma and bed rest (Evans, 1999). While resistance training exercises have not yet been shown to have the same effects on risks of chronic diseases, their effects on muscle strength are an indication to include them in exercise prescriptions, in addition to activities that promote cardiovascular fitness and flexibility.

As noted earlier, carbohydrate is the preferred energy source for working human muscle (Figure 12-7) and is often utilized in preference to body fat stores during exercise (Bergman and Brooks, 1999). However, over the course of a day, the individual is able to appropriately adjust the relative uses of glucose and fat, so that recommendations for nutrient selection for very active people, such as athletes and manual laborers, are generally the same as those for the population at large. With regard to the impact of activity level on energy balance, modifications in the amounts, type, and frequency of food consumption may need to be considered within the context of overall health and fitness objectives. Such distinct objectives may be as varied as: adjustment in body weight to allow peak performance in various activities, replenishment of muscle and liver glycogen reserves, accretion of muscle mass in growing children and athletes in training, or loss of body fat in overweight individuals. However, dietary considerations for active persons need to be made with the goal of assuring adequate overall nutrition.

Following the recently released joint position statement of the American College of Sports Medicine, American Dietetics Association, and Dietitians of Canada (ACSM et al., 2000), water and fluids containing carbohydrates and electrolytes may be consumed immediately prior to, during, and after physical activity. For instance, a collegiate swimmer arriving on an empty

Front Matter (R1-R26)

Summary (1-20)

1. Introduction to Dietary Reference Intakes (21-37)

2. Methods and Approaches Used (38-52)

3. Relationship of Macronutrients and Physical Activity to Chronic Disease (53-83)

4. A Model for the Development of Tolerable Upper Intake Levels (84-106)

5. Energy (107-264)

6. Dietary Carbohydrates: Sugars and Starches (265-338)

7. Dietary, Functional, and Total Fiber (339-421)

8. Dietary Fats: Total Fat and Fatty Acids (422-541)

9. Cholesterol (542-588)

10. Protein and Amino Acids (589-768)

11. Macronutrients and Healthful Diets (769-879)

12. Physical Activity (880-935)

13. Applications of Dietary Reference Intakes for Macronutrients (936-967)

14. A Research Agenda (968-971)

Appendix A: Glossary and Acronyms (972-977)

Appendix B: Origin and Framework of the Development of Dietary Reference Intakes (978-984)

Appendix C: Acknowledgments (985-987)

Appendix D: Dietary Intake Data from the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994 (988-1027)

Appendix E: Dietary Intake Data from the Continuing Survey of Food Intakes by Individuals (CSFII) 1994-1996, 1998 (1028-1065)

Appendix F: Canadian Dietary Intake Data, 1990-1997 (1066-1075)

Appendix G: Special Analyses for Dietary Fats (1076-1077)

Appendix H: Body Composition Data Based on the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994 (1078-1103)

Appendix I: Doubly Labeled Water Data Used to Predict Energy Expenditure (1104-1202)

Appendix J: Association of Added Sugar Intake and Intake of Other Nutrients (1203-1225)

Appendix K: Data Comparing Carbohydrate Intake to Intake of Other Nutrients from the Continuing Survey of Food Intakes by Individuals (CSFII), 1994-1996, 1998 (1226-1243)

Appendix L: Options for Dealing with Uncertainties (1244-1249)

Appendix M: Nitrogen Balance Studies Used to Estimate the Protein Requirements in Adults (1250-1258)

Biographical Sketches of Panel and Subcommittee Members (1259-1274)

Index (1275-1318)

Summary Tables, Dietary Reference Intakes (1319-1331)