Metabolic Control Of Eating Energy Expenditure And The Bioenergetics Of Obesity

Abstract: A comprehensive yet uncomplicated discussion of obesity is presented for the average adult as part of a series called "Medicine for the Layman." Although the specific causes of obesity are unknown, many factors, such as genetics and environment, influence the condition. More is known about the health consequences of obesity in terms of increased risk of diabetes, cardiovascular diseases and emotional stress. Obesity is defined; the functions of the human body which help determine the numbers and size of fat cells in adipose tissue (hypertrophic and hyperplastic obesity) are described. The balance of caloric intake and energy expenditure for each individual is emphasized. Further research needs are identified. The information is reinforced by a question and answer section and color cartoons.

During the last two decades, the prevalence of obesity has dramatically increased in western and westernized societies. Its devastating health consequences include hypertension, cardiovascular diseases, or diabetes and make obesity the second leading cause of unnecessary deaths in the USA. As a consequence, obesity has a strong negative impact on the public health care systems. Recently emerging scienti?c insight has helped understanding obesity as a complex chronic disease with multiple causes. A multileveled gene–environment interaction appears to involve a substantial number of susceptibility genes, as well as associations with low physical activity levels and intake of high-calorie, low-cost, foods. Unfor- nately, therapeutic options to prevent or cure this disease are extremely limited, posing an extraordinary challenge for today’s biomedical research community. Obesity results from imbalanced energy metabolism leading to lipid storage. Only detailed understanding of the multiple molecular underpinnings of energy metabolism can provide the basis for future therapeutic options. Numerous aspects of obesity are currently studied, including the essential role of neural and endocrine control circuits, adaptive responses of catabolic and anabolic pathways, metabolic fuel sensors, regulation of appetite and satiation, sensory information processing, transcriptional control of metabolic processes, and the endocrine role of adipose tissue. These studies are predominantly fuelled by basic research on mammalian models or clinical studies, but these ?ndings were paralleled by important insights, which have emerged from studying invertebrate models.

Energy balance can be maintained by adapting energy intake to changes in energy expenditure and vice versa, where short-term changes in energy expenditure are mainly caused by physical activity. Questions are whether physical activity is affected by over and under-eating, is intake affected by an increase or a decrease in physical activity, and does overweight affect physical activity? Presented evidence is largely based on studies where physical activity is quantified with doubly labeled water. Overeating does not affect physical activity while under-eating decreases habitual or voluntary physical activity. Thus, it is easier to gain weight than to lose weight. An exercise induced increase in energy requirement is compensated by intake while a change to a more sedentary routine does not induce an equivalent reduction of intake and generally results in weight gain. Overweight and obese subjects have similar activity energy expenditures than lean people despite they move less. There are two options to reverse the general population trend for an increasing body weight, reducing intake or increasing physical activity. Based on the results presented, eating less is most effective for preventing weight gain, despite a potential negative effect on physical activity when reaching a negative energy balance.​

Metabolic Regulation looks in detail at how molecules, cells and tissues operate collectively in human health and disease, using an approach that has become known as ‘integrative physiology’. Since the publication of the first edition of this extremely well received book, the understanding of how metabolism is regulated has developed substantially in several ways, for example with the discovery of the hormone leptin, and also in the continuing advances in the understanding of gene expression. Full details of these and other new advances are included in this fully updated edition. Carefully laid out with relevant and clearly explained examples, and containing much new material, this new edition covers in an integrated way: concepts and mechanisms, digestion and intestinal absorption, organs and tissues, endocrine organs and hormones, the integration of carbohydrate, fat and protein metabolism, the nervous system and metabolism, lipoprotein metabolism, diabetes mellitus, energy balance and body weight regulation and how the body copes with some extreme situations. The author, Keith Frayn, who has many years’ experience teaching and researching in this subject, has written a book of great clarity, which is an extremely valuable tool for scientists, practitioners and students working and studying across a broad range of allied health sciences including nutrition, dietetics, sports science and nursing. Students of medicine, physiology, biochemistry and biological sciences will also find much of great use and interest in this book. All libraries in research establishments, universities and medical schools where these subjects are studied and taught should have multiple copies of this excellent book on their shelves. Keith Frayn is Professor of Human Metabolism at the University of Oxford, UK.Reviews of the First Edition ‘This is an excellent textbook’: Trends in Endocrinology and Metabolism ‘The coverage is excellent for students following courses such as nutrition and human biology’:Biologist ‘This book is ideal for medical students’:Australian Society for Biochemistry and Molecular Biology

Abstract: Information about energy balance in man is presented for professionals concerned with human obesity--physicians, dieticians, biochemists, physiologists,psychologists, physiotherapists, and others. The use and misuse of methods for measuring energy intake and output arediscussed. Factors affecting energy intake and factors affecting energy output are also discussed. Also considered are the composition, measurement, and control of energy stores. The treatment of obesity is explained.

The fact that about 30-40% of the adults in the Western world are overweight or obese testifies to the frequency of the disturbances in body weight regulation. Scientists have established that caloric intake, macronutrient composition of the diet, basal and resting metabolic rate, thermic response to food, energy expenditure associated with movement and physical activity, and preferential storage of the surplus of calories as fat or lean tissues are critical determinants of energy balance and body weight. While much has been learned, the field is poised for major advances with the advent of a variety of imaging techniques, progress in quantitative and molecular genetics, use of transgenic rodent models and of breeding experiments with informative inbred strains, availability of stable isotopes for metabolic and behavioral studies, and a growing number of useful experimental animal and human models. This volume takes an integrative approach to obesity. It is structured around four major topics: (1) the animal and human models currently available for the study of body weight regulation with their strengths and limitations, (2) the molecular and genetic basis of the regulation of body weight, (3) the metabolic and physiological mechanisms involved, and (4) the behavioral and social determinants. The 13 background papers provide a critical overview of the present knowledge base while the group reports summarize the extensive deliberations of 38 international experts. Particular emphasis has been given to promising research areas and on the advances needed to ensure a better understanding of the biological and behavioral mechanisms of the regulation of body weight, with a particular emphasis on overweight and obesity.

Applied Veterinary Clinical Nutrition Well-referenced clinical resource for canine and feline nutrition, with expansions throughout and two new chapters covering birds and small mammals. Fully revised to reflect new advances and information throughout, the Second Edition of Applied Veterinary Clinical Nutrition presents current, authoritative information on all aspects of small companion animal nutrition. The book provides clinically oriented solutions for integrating nutrition into clinical practice, with introductory chapters covering the foundation and science behind the recommendations and extensive references for further reading in every chapter. With contributions from more than 25 leading veterinary nutritionists, Applied Veterinary Clinical Nutrition covers topics such as: Integration of nutrition into clinical practice, basic nutrition, energy requirements, and pet food regulations in North America and Europe that also apply to many other regions Using and reviewing pet food labels and product guides, feeding the healthy dog and cat, and abridged clinical nutrition topics for companion avian species & small mammals Commercial and home-prepared diets, and nutritional management of body weight and orthopedic, skin, and gastrointestinal diseases Nutritional management of exocrine, hepatobiliary, kidney, lower urinary tract, endocrine, cardiovascular, and oncological diseases as well as enteral and parenteral nutrition A valuable resource on the principles of small animal nutrition and feeding practices in health or disease, Applied Veterinary Clinical Nutrition is a widely trusted and practical daily reference for veterinary practitioners including specialists, residents, and students seeking expert information on feeding their canine, feline, avian, and small mammalian patients.