THE EFFECTS OF ENVIRONMENTAL AND PHYSICAL STRESS ON ENERGY EXPENDITURE, ENERGY INTAKE, AND APPETITE by Iva Mandic A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Department of Exercise Science University of Toronto © Copyright by Iva Mandic (2018) The effects of environmental and physical stress on energy expenditure, energy intake, and appetite Iva Mandic Doctor of Philosophy The Graduate Department of Exercise Sciences University of Toronto 2018 Abstract Body weight loss occurs frequently in military personnel engaged in field operations. When this weight loss is rapid, or extensive it is associated with health and performance decrements. While the nature of military work does not allow for energy expenditure (EE) to be freely altered, energy intake (EI) can be increased to match EE and prevent weight loss. Therefore a primary objective of the current dissertation was to develop a physiological and empirical basis to facilitate informed estimates of the EI that would be required to offset the EE demand of military tasks during field operations. Three different approaches were undertaken: 1) The energy costs of 46 infantry tasks were measured; the results should reduce the dependency on less accurate predictions. 2) The impact of ambient temperature on EE of the tasks was minimal (~3%) when the ambient temperature was between -10°C and 30°C. This indicates that caloric supplementation of field rations on account of temperature is likely unnecessary during short-term operations occurring within this temperature range; and, lastly 3) A simple algorithm based on accelerometry and heart rate was developed to assess EE in the field. The application of this algorithm should improve EE/EI matching. ii Unfortunately military personnel engaged in arduous field operations usually experience an energy deficit, even when food availability is adequate. Voluntary anorexia can ultimately thwart nutrition optimization in the field, therefore the role of appetite was also explored. While hormonal responses pointed towards appetite suppression with increased physical activity levels (with a partial blunting of that response in the cold) and subjective appetite was the lowest in the heat and highest in the cold, actual EI was unchanged regardless of ambient temperature or whether the participant was sedentary or active. This research demonstrated that even in the most favourable scenarios military personnel engaged in typical infantry tasks may under eat and plunge into a negative energy balance. These results suggest that factors other than food availability and palatability, such as policy or procedural changes should be considered in addressing voluntary anorexia in the field in military personnel. iii Acknowledgements First and foremost, I would like to thank my supervisor Dr. Ira Jacobs, for giving me the opportunity to work on such an interesting and involved research contract. Ira, thank you for being confident in my abilities even when I wasn’t, your continued trust and support have truly shaped the scientist I am today. Thank you for always challenging me and for knowing exactly how much guidance to provide. I have learned so much from you professionally and personally that I could not imagine having a better mentor throughout my PhD than you. I am also grateful for my co-supervisor Dr. Catherine Amara, who was incredibly understanding and supportive when the opportunity to work with the Canadian Armed Forces came. Cathy, I truly enjoyed working with you at the beginning of my PhD and really appreciate the opportunities you provided me with. I always felt like your door was open to me, and I’m very thankful for all of your support and guidance. I’m also grateful for your many thought- provoking questions that forced me to consider a different angle and ultimately broadened my field of knowledge. I would like to give special thanks to Dr. Mary L’Abbé and Dr. Greg Wells for serving on my committee and for providing me with useful feedback every step of the way. Mary, thank you for reviewing numerous papers, proposals, and ethics submissions, I really value your perspective and feel that your input, and attention to detail focused my work. Greg, thank you for asking me difficult, theoretical questions and pushing me outside my comfort zone. I was very fortunate to have a committee that challenged me and was so dedicated to my success. To my examiners, Dr. Harris Lieberman and Dr. Karl Zabjek, thank you for your insightful comments and for your genuine interest in my dissertation. Dr. Lieberman, I have read much of your work, and it’s incredibly humbling to receive such high praise from someone like you. I would also like to thank Dr. Paul Corey for helping me gain a deeper understanding of different statistical methods which ultimately allowed me to develop the energy expenditure algorithm. Paul, I’m thankful for the time and energy you spent helping me with my rather complicated dataset. iv To my wonderful collaborator Mavra Ahmed, I feel so fortunate to have had you by my side throughout our long and laborious data collection process. Whether we were working >12-h days, or waddling around in enormous snowsuits in Meaford, I always felt better knowing that you’d be there with me. Thank you for being a great colleague, and an even better friend. I would like to acknowledge the Canadian Armed Forces, and in particular the many individuals who were always on hand to explain military jargon, assist with data collection, or participate as research subjects. I sincerely appreciate all of the time and effort you put into this project. In addition, I would also like to acknowledge the valuable contribution of Defence Research and Development Canada staff. Thank you for collaborating with me, for supporting this project, and for seeing it through. Specifically, I’d like to acknowledge Dr. Len Goodman and Dr. Shawn Rhind for their continued support. Len, thank you for jumping in whenever we were short staffed, I’ve enjoyed our many conversations, and appreciate your commitment to this research. Dr. Shawn Rhind, thank you for your selfless dedication to my success, you were under no obligation to help me, yet you did, tremendously. Thank you for your insightful suggestions, and for providing me with whatever I needed to analyze my blood samples. To my friends and family, thank you for your love and understanding when I would disappear for months at a time to work on this dissertation. I also truly appreciate your patience and your avoidance of that joyless question “when will you be done?” Finally, I would like to express my deepest gratitude to my husband Amerigo. Thank you for providing me with the means to analyze my millions of rows of data, I don’t know how I would’ve done it without you. Thank you for taking care of me when I was too busy to take care of myself, for building me up when I felt defeated, for teaching me how to relax, and for your constant love and support throughout this whole journey. No words can express how grateful I am to have you by my side. Funding Acknowledgement This research was funded by a research contract W7719-125107/001/TOR awarded to Dr. Ira Jacobs at the University of Toronto by the Canadian Department of National Defence. The research conducted was done in collaboration with Defence Research and Development Canada, and Mavra Ahmed, and Mary L’Abbé from the Department of Nutritional Sciences at the University of Toronto. v Table of Contents Abstract .......................................................................................................................................... ii Acknowledgements ....................................................................................................................... iv List of Abbreviations ................................................................................................................... xii List of Tables .............................................................................................................................. xiii List of Secondary Tables .............................................................................................................. xv List of Figures ............................................................................................................................. xvi List of Appendices .................................................................................................................... xviii Chapter One: Introduction .............................................................................................................. 1 1.1 Overview of Dissertation .......................................................................................................... 1 Chapter Two: Literature Review .................................................................................................... 3 2.1 Energy Balance ......................................................................................................................... 3 2.1.1Physiological and Psychological Effects of Weight Loss....................................................... 4 2.1.2 Typical Weight Loss in Military Personnel ........................................................................... 6 2.2 The Canadian Combat Ration Program .................................................................................... 7 2.2.1Energy content of supplied food ............................................................................................