Progress 09/01/05 to 08/31/08
OUTPUTS: 1. Outputs completed. Obesity can be viewed as a consequence of a slow but steady positive calorie balance resulting from slightly more food intake and/or slightly less energy expenditure. The introduction of doubly-labeled water analysis has documented that food records often under-report the calories needed to maintain weight, and that this is a particularly bad method in overweight individuals. To determine whether we could narrow the difference between food intake and energy expenditure by doubly-labeled water we recruited 10 healthy dietitians and 10 control subjects. They recorded their food intake over two separate 7-day periods. In one period we measured energy expenditure by doubly-labeled water. The dietitians were about 6% below measured energy expenditure and the non-dietitians were about 14% below. We have used the 7-day food records from each group to examine the periodicity of food intake. Fat intake was positively related to calorie intake, supporting our overall hypothesis. That is, when women ate more fat and they also ingested more calories. In this study we also found a periodicity in caloric intake that cycled with a 3- to 4-day rhythm. This means there is another regulatory system involved in feeding besides the short-term ones that have been so intensively studied. In addition to dietary fat, animal and human studies show that dietary protein is an important factor in regulation of body weight and that both high- and low-protein diets are less efficiently stored as fat than a normal-protein diet. To test this idea we began an overfeeding study in which volunteers were recruited to spend 9-10 weeks on the metabolic ward. These 16 men and 8 women were randomized to one of three diets: A 5% protein diet, a 15% protein diet or a 25% protein diet. After weight stabilization, measurement of metabolic rate and doubly-labeled water, and body composition they were overfed 1000 kcal/d for 56 days. They were on continuous urine collections and wore accelerometers throughout. Measurements of doubly-labeled water, body composition by DXA and energy expenditure in the respiration calorimeter were taken on three separate occasions during overfeeding. The data base from collection of data has been finished, and data analysis is actively underway. 2. How results have been disseminated. The periodicity-of-food-intake study has yielded a publication accepted by the American Journal of Clinical Nutrition for 2008 and should reach the scientific audience for whom the studies are relevant. Previously the data on food intake and under-reporting were published in the Journal of the American Dietetic Association. This study also served as a training experience for a graduate student from Brazil who worked on the initial design and execution of the study. So far from this overfeeding project we have had one abstract presented as a poster to the relevant Obesity Society during their meeting in Phoenix in October 2008. As data analysis proceeds, additional papers will appear. This study has served as a training study for two young post-doctoral fellows and the data are serving as part of the doctoral dissertation for a student in statistics. PARTICIPANTS: Individuals: George A. Bray, M.D., Co-Principal Investigator Steven R. Smith, M.D., Co-Principal Investigator Marlene M Most, Ph.D., Chief Dietitian Jennifer Rood, Ph.D. Chief of the Clinical Laboratory Partner Organizations: LSU Agricultural Research Center, Baton Rouge, LA Collaborators and Contacts: None Training or Professional Development: Clinical Nutrition Research Center NIH-Training Grant TARGET AUDIENCES: Target audiences: This project serves the scientific community through the publication and presentation of the scientific research. It serves academic associations, such as The Obesity Society, the American Diabetes Association, the Nutrition Society by providing information at annual meetings. Efforts: The major educational outreach of this proposal is through the local training grant and through the LSU Graduate program in Nutrition Education. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
1. How findings, results, techniques or other products that were developed or extended from the project generated or contributed to an outcome/impact. The personnel in the metabolic ward and stable isotope laboratory on which these important studies were conducted and on which they depended were partially supported by this USDA grant. Use of these funds for this purpose allowed us to conduct the detailed metabolic studies that served as the basis for our abstracts and publications. 2. Results of the project evaluation. In order to maintain scientific excellence in our studies, we have had them reviewed by an external advisory group at least every 2 years. The most recent external advisory group consisted of Dr. Robert Henry from the University of California, San Diego, CA, who has worked on the metabolic responses of muscle to insulin resistance and on human obesity; Dr. Holly Wyatt from the University of Colorado in Denver, CO. Dr. Wyatt plays an important role in the Endocrine Society in advising them on the obesity components of the Society meeting. She is widely recognized for her clinical and research studies on exercise and behavioral strategies. Dr. Ken Fujioka is from the Scripps Clinic in La Jolla, CA, where he serves to direct the obesity program. These three reviewers were very positive about the direction of the program, and in particular the overfeeding - protein study, which was in active development at the time of their last review. 3. How resources and activities helped to produced project outputs and achieve project outcomes and impacts. Three key elements are particularly important in the success of these two projects. The first is the dietary input provided by Dr. Catherine Champagne, Dr. Marlene Most, and their colleagues. These groups were responsible for developing diets used in the metabolic ward studies and evaluating the food intake records from the cyclicity study. The second key element is the stable isotope laboratory that was required for the measurement of doubly-labeled water for the cyclicity study and for the overfeeding study. The metabolic chambers and metabolic ward were critical for conducting the overfeeding-protein study.
- Bays, H.E, J.M. Gonzalez-Campoy, G.A. Bray, A.E. Kitabchi, D.A. Bergman, A.B. Schorr, H.W. Rodbard, R.R. Henry. The Pathogenic Potential of Adipose Tissue and the Metabolic Consequences of Adipocyte Hypertrophy and Increased Visceral Adiposity. Expert Rev Cardiovasc Ther 6:343-368, 2008.
- Bray, G.A. J-P. Flatt, J. Volaufova, J.P. DeLany, C.M. Champagne. Corrective responses in human food intake identified from an analysis of 7-day food intake records. Am J Clin Nutr 2008 in press.
- Lilian de Jonge, Olga Sereda, Jennifer C Rood, Steven R Smith. 24-H Urinary C-Peptide Excretion, Dietary Intake and Insulin Sensitivity: The PROOF Study. Presented at the Obesity Society annual scientific meeting, Phoenix, AZ, 2008.
- Moro, C., Bajpeyi, S. & Smith, S. R. Determinants of intramyocellular triglyceride turnover: implications for insulin sensitivity. Am J Physiol Endocrinol Metab 294: E203-213; 2008.
- Rood, J. & Smith, S. R. Triglyceride concentrations and endotoxemia. Am J Clin Nutr. Jul;88(1):248-9; 2008.
- Koska J, Stefan N, Votruba SB, Smith SR, Krakoff J, Bunt JC. Distribution of Subcutaneous Fat Predicts Insulin Action in Obesity in Sex-specific Manner. Obesity (Silver Spring). Sep;16(9):2003-9; 2008.
- Koska J, Stefan N, Permana PA, Weyer C, Sonoda M, Bogardus C, Smith SR, Joanisse DR, Funahashi T, Krakoff J, Bunt JC. Increased fat accumulation in liver may link insulin resistance with subcutaneous abdominal adipocyte enlargement, visceral adiposity, and hypoadiponectinemia in obese individuals. Am J Clin Nutr. Feb;87(2):295-302; 2008.
- Civitarese, A. E., Smith, S. R. & Ravussin, E. Diet, energy metabolism and mitochondrial biogenesis. Curr Opin Clin Nutr Metab Care 10: 679-687; 2007.
Progress 09/01/06 to 08/31/07
OUTPUTS: Activities: This grant focuses on obesity and conducts in-patient and out-patient research. We have admitted individuals to our metabolic unit with facilities and used this to mentor younger post-doctoral fellows and one graduate student. Events: The two Principal Investigators, the Chief Dietitian, and Chief of the Clinical Laboratory have all participated in many national conferences, including those funded by the American Association of Clinical Chemists, the American Heart Association, the American Diabetes Association, the American College of Cardiology. Services: USDA investigators played major roles in the construction and operation of the In-patient Respiration Calorimeters and the development of the newly installed Magnetic Resonance Spectrometer. The facilities support the USDA research and are supported through other institutional support and other Federal grants. Products: New scientific knowledge was created in the form of peer-reviewed manuscripts
(publications), and book chapters. Databases of clinical metabolic data were created and coupled to tissue repositories collected under the USDA proposal; the latter resources led to collaborations with other USDA units (e.g., investigators at the Western ARS unit in California). A new in vitro cell culture model of exercise - fat burning systems was created as a spin-off of these efforts - this allows for the exploration of genetic susceptibility to the lipotoxic effects of high-fat diets. Dissemination: We have two annual health fairs for residents in Baton Rouge, and the USDA program faculty participate in this activity.
PARTICIPANTS: Individuals: George A. Bray, M.D., Co-Principal Investigator Steven R. Smith, M.D., Co-Principal Investigator Marlene M Most, Ph.D., Chief Dietitian Jennifer Rood, Ph.D. Chief of the Clinical Laboratory Partner Organizations: LSU Agricultural Research Center, Baton Rouge, LA Collaborators and contacts: None Training or professional Development: Clinical Nutrition Research Center NIH-Training Grant
TARGET AUDIENCES: Target Audiences: This project serves the scientific community through the publication and presentation of the scientific research. It serves academic associations, such as The Obesity Society, the American Diabetes Association, the Nutrition Society by providing information at annual meetings. Efforts: The major educational outreach of this proposal is through the local training grant and through the LSU Graduate program in Nutrition Education.
This project studies the role of protein and fat in overfeeding diets on metabolic responses and the genetic causes of these responses. Results show that 3 days of a high-fat diet decreased mRNA in skeletal muscle & increased transcription of 2 key inhibitors of glucose conversion through the tricarboxylic acid cycle (PFKFB3 and PDHK4). A 2nd group of genes involved in mitochondrial fatty acid oxidation, the OXPHOS genes, are down-regulated in subjects eating a high-fat diet, suggesting how high-fat diets might produce obesity and the metabolic syndrome. For the study on 3 levels of protein, data are complete and being analyzed. The study on effect of exercise/no exercise on gene expression in people eating high-fat diets has IRB approval and subjects are being recruited. Obesity clearly results from positive energy balance. We must explore the response to positive energy balance when people gain weight and become obese. When body weight increases, expenditure of
energy rises to dissipate excess calories through known mechanisms including increased spontaneous physical activity. The role of diet composition in the metabolic and genetic response to over-feeding and energy dissipation in humans is unknown but studies suggest amount of protein is important, with both high- and low-protein diets being less efficient in deposition of fat and lean tissue than modest-protein diet. We predict a) high- and low-protein diets will result in less weight gain compared to moderate-protein diet during high-fat overfeeding, b) increased energy expenditure and fidgeting will be greater in high- and low-protein diets than in moderate-protein diet, and c) average fat cell size and gene expression pattern in adipose tissue, skeletal muscle, and peripheral blood mononuclear cells will predict which subjects gain the most weight (and fat mass) independent of diet protein. We will test this by overfeeding at 40% above energy requirements for energy balance using 3
diets: a low (5%)protein diet; a normal (15%)protein diet; or a high (25%)protein diet. Changes in body weight and composition and energy expenditure and its components will be measured throughout the study. Baseline characteristics (fat cell size, gene expression pattern, family history of obesity) will be determined as a basis for predicting degree of weight/fat gain during overfeeding. In the high-fat diet protocol, subjects eat standard 35% fat diet for 3 days, enter the chamber, and after 1 day of baseline measures, dietary fat is raised for the next 3 days to 50% of energy while energy intake is clamped to match energy expenditure. RQ (fat oxidation) is measured without the confounding variable of food intake & caloric excess. Adipose tissue and skeletal muscle are needle-biopsied after local anesthesia. The techniques for measuring muscle metabolism in cells grown in vitro were shown to work and provide differences in muscle types between subjects. For the final study on
exercise and high-fat diet, we predict that exercise will blunt genetic responses in PFKFB3 and PDHK4 and in OXPHOS genes, providing an explanation for why exercise facilitates oxidation of fat and conservation of glucose.
- Bray, G.A. Drug Management of Obesity IN: Surgical Management of Obesity H. Buchwald,G.S. M. Cowan, Jr and W.J. Pories (eds). Philadelphia: Saunders (Elsevier) 2007. Pp73-82.
- Bray, G.A. and C.M. Champagne. The complexity of obesity: Beyond energy balance. IN:Williams' Essentials of Nutrition & Diet Therapy E.D. Schlenker and S. Long (eds). St. Louis:Mosby (Elsevier) ninth edition, 2007. Pp369-383.
- Kennedy B.M., S. Paeratakul, D.H. Ryan G.A. Bray. Socioeconomic status and health disparityin the United States. J Human Behav Soc Envir 15(2/3):13-23; 2007.
- Bray, G.A. and F.L. Greenway. Pharmacological treatment of the overweight patient. Pharm Rev 59:151-184; 2007
- Bray, G.A. and B.M. Popkin. Epidemics of obesity and metabolic disorders: Are dietary fats or sugars involved? Curr Nutr Food Sci 3:113-121; 2007
- Bray GA, and F.L. Greenway. Weight loss drugs: current and on the horizon. IN: Treatment of the Obese Patient, R.F. Kushner and D.H. Bessesen (eds) IN The Series: Contemporary Endocrinology , P.M. Conn, (ed). Humana Press, Totowa, NJ, 2007. Pp 241-368.
- Bray, G.A. and D.H. Ryan. Drug treatment of the overweight patient. Gastroenterology 132:2239-2252; 2007.
- Bray, G.A. Medical Therapy for Obesity - Current Status and Future Hopes. (Yanigasawa, RT and LeRoith, D (eds). Med Clin NA 91:1225-1253; 2007.
- Arguin, H., G.A. Bray, J.C. Lovejoy J.C. Peters, R.J. Jandacek, A. Tremblay. Effect of olestra on plasma organochloride concentrations during a weight-reducing program. Obesity 15:A89; 2007
- Ukropcova, B., Sereda, O., de Jonge, L., Bogacka, I., Nguyen, T., Xie, H., Bray, G. A. & Smith, S. R. Family history of diabetes links impaired substrate switching and reduced mitochondrial content in skeletal muscle. Diabetes 56: 720-727; 2007
- Bray, G. A., Most, M., Rood, J., Redmann, S. & Smith, S. R. Hormonal responses to a fast-food meal compared with nutritionally comparable meals of different composition. Ann Nutr Metab 51: 163-171; 2007 Kaaman, M., Sparks, L. M., van Harmelen, V., Smith, S. R., Sjolin, E., Dahlman, I. & Arner, P.(2007) Strong association between mitochondrial DNA copy number and lipogenesis in human white adipose tissue. Diabetologia (in press, 2007).
- Trevaskis, J. L., Gawronska-Kozak, B., Sutton, G. M., McNeil, M., Stephens, J. M., Smith, S. R. & Butler, A. A. Role of adiponectin and inflammation in insulin resistance of Mc3r and Mc4r knockout mice. Obes Res (in press, 2007).
- Koska, J., Stefan, N., Permana, P. A., Weyer, C., Sonoda, M., Bogardus, C., Smith, S. R., Joanisse, D. R., Funahashi, T. & Krakoff, J. Increased fat accumulation in liver may link insulin resistance with subcutaneous abdominal adipocyte enlargement, visceral adiposity and hypoadiponectinemia in obese individuals. Am J Clin Nutr (in press, 2007).
- Wendland, E. M., Ravussin, E., Greenway, F. L., Bray, G. A. & Smith, S. R. Adipocyte size is associated with metabolic syndrome independent of fatness. J Clin Endocrinol Metab (in revision, 2007).
- Pasarica, M., Sparks, L. M., Sereda, O., de Jonge, L., Thomas, S., Loggins, H., Xie, H., Miles, J. M. & Smith, S. R. Sexual Dimorphism in Metabolic Flexibility: A Role for Adipose Tissue. J Clin Endocrinol Metab (in revision, 2007).
- Moro, C., Sparks, L. M., Ukropcova, B., Bajpeyi, S., Civitarese, A. E., Hulver, M. W. & Smith, S. R. Activation of exercise-signaling pathways in human primary myocytes induces structural and functional changes in lipid metabolism and insulin sensitivity. AJP-EM (in review, 2007).
- Higami, Y., Barger, J. L., Page, G. P., Allison, D. B., Smith, S. R., Prolla, T. A. & Weindruch, R. Energy restriction lowers the expression of genes linked to inflammation, the cytoskeleton, the extracellular matrix, and angiogenesis in mouse adipose tissue. J Nutr 136: 343-352; 2006.
- Smith, S. R. & Wilson, P. W. F. Free fatty acids and atherosclerosis: Guilty or Innocent? J Clin Endocrinol Metab 91: 2506-2508; 2006.
- Larson-Meyer, D. E., Smith, S. R., Heilbronn, L. K., Kelley, D. E., Ravussin, E. & Newcomer, B. R. Muscle-associated Triglyceride Measured by Computed Tomography and Magnetic Resonance Spectroscopy. Obes Res 14: 73-87; 2006.
- Solinas, G., Summermatter, S., Mainieri, D., Gubler, M., Montani, J. P., Seydoux, J., Smith, S. R. & Dulloo, A. G. Corticotropin-releasing hormone directly stimulates thermogenesis in skeletal muscle possibly through substrate cycling between de novo lipogenesis and lipid oxidation. Endocrinology 147: 31-38; 2006.
- Ptitsyn, A., Hulver, M., Cefalu, W., York, D. & Smith, S. R. Unsupervised clustering of gene expression data points at hypoxia as possible trigger for metabolic syndrome. BMC Genomics 7: 318; 2006.
Progress 09/01/05 to 09/01/06
US Government agencies have called the rising prevalence of obesity an epidemic. Dietary fat has long been thought to play a role in this epidemic. Understanding the relation of dietary fat from animal and plant sources and how the body responds to them is the focus of our studies. We are testing the response of human subjects to changes in the quantity and quality of dietary fat on fat storage and the relationship of this fat storage to different amounts of dietary protein and exercise in a grant titled Dietary Fat and Central Adiposity. Central adiposity refers to the fat stored on or within the abdomen. The intraabdominal part of this fat is particularly important because it predicts risks for ill-health. Our work has already yielded important new ideas. We have identified several predictors for the storage of body fat including a low maximal VO2, a high fasting insulin, and a high fasting respiratory quotient. Of particular interest is the fact that increased
visceral fat stores predict further fat stores, as though it were a vicious cycle. We have shown that these predictors are present in overweight men and women, as well as normal weight ones. Using muscle biopsies from the individuals eating different levels of dietary fat, we have identified two key pathways affected by a high fat diet. Three days of a high fat diet decreased mRNA in skeletal muscle for a cluster of genes involved in glucose uptake and oxidation and increased transcription of a key inhibitor of glucose conversion through the Phosphoenolpyruvate Dehydrogenase enzyme complex (PDHK4). These genes cluster with a second group of genes involved in mitochondrial fatty acid oxidation called the OXPHOS genes. These same genes are down regulated in healthy young volunteers who are eating a high fat diet suggesting a mechanism by which high fat diets might be involved in the genesis of obesity and central adiposity. We have also shown that the maximal rate of fat oxidation
during sleep when eating a high fat diet and mitochondrial DNA content are reduced in subjects with a family history of diabetes, supporting the concept of an intrinsic defect in oxidative capacity of muscle fat.
These studies on response to dietary fat have identified several important groups of genes that relate to whether people store fat and have shown that individuals from families with a history of diabetes respond differently, providing the potential for targeting high risk people.
- Popkin, B.M., Armstrong, L.E., Bray, G.A., Caballero, B., Frei, B. and Willett, W.C. 2006. A new proposed guidance system for beverage consumption in the United States. Am J Clin Nutr 83:529-542.
- McElroy, S.L, Allison, D.B. and Bray, G.A. (eds). 2006. Obesity and Mental Disorders. New York: Taylor and Francis Group, pp i-xviii, 1-462.
- Bray, G.A. Obesity is a major health problem: Causes and natural history. 2006. IN: Obesity and Mental Disorders, S.L. McElroy, D.B. Allison and G.A. Bray. New York: Taylor and Francis Group:1-20.
- Bray, G.A. and D.H. Ryan. Medical approaches to treatment of the obese patient. 2005. IN: Obesity and Diabetes, C.S. Mantzoros (ed). Chap 26 Totowa, NJ: Humana Press, pp 457-468.
- Bray, G.A. and Bellanger, T. 2006. Epidemiology, trends, and morbidities of obesity and the metabolic syndrome. Endocrine 29:109-117.
- Poirier, P.T., Giles, D., Bray, G.A., Hong, Y., Stern, J.S., Pi-Sunyer, F.X. and. Eckel, R.H. 2006. Obesity and cardiovascular disease: pathophysiology, evaluation and effect of weight loss. Arterio Thomb Vasc Biol 26:968-976.
- Popkin, B.M., Armstrong, L.E., Bray, G.A., Caballero, B., Frei, B. and Willett, W.C. 2006. Response to C Weaver et al. Am J Clin Nutr 84:1246-8.
- Bray, G.A. 2006. Serotonergic drugs for the treatment of obesity. J Pharmacological Sci 101(Suppl 1:14, (Abs).
- Bray, G.A. 2006. Obesity: the disease. J Med Chem 49:4001-7.
- Bray, G.A. and Hansen, B.C. 2006. The 20th anniversary of the International Association for the Study of Obesity: A review of two decades. Obesity Newsletter;9:13-15.
- Sparks, L., Ukropcova, B., Xie, H., Smith, J., Hymel, D., Bray, G., Miles, J. and Smith, S. 2006. Impaired insulin suppression of adipose tissue lipolysis. Obesity 14:A1 (Abs).
- Sparks, L.M., Xie, H., Koza, R.A., Mynatt, R., Bray, G.A. and Smith, S.R. 2006. High-fat/low-carbohydrate diets regulate glucose metabolism via a long-term transcriptional loop. Metabolism 55:1457-1463.
- Bray, G.A. 2006. Cardiometabolic Syndrome. J Am Assoc Physician Asst(Suppl).
- Bray, G.A. and Ryan, D.H. (eds). 2006. Overweight and the Metabolic Syndrome: From Bench to Bedside. New York: Springer Science & Business Media.
- Poirier, P., Giles, T.D., Bray, G.A., Hong, Y., Stern, J.S. and Eckel, R.H. 2006. Obesity and cardiovascular disease: pathophysiology, evaluation, and effect of weight loss: an update of the 1997 American Heart Association Scientific Statement on Obesity and Heart Disease from the Obesity Committee of the Council on Nutrition, Physical Activity, and Metabolism. Circ 113:898-918.
- Bray, G.A. and Ryan, D.H. 2006. Evaluation of the overweight and obese patient. IN: Overweight and the Metabolic Syndrome: From Bench to Bedside. New York: Springer Science & Business Media;169-186.
- Greenway, F.L. and Bray, G.A. 2006. A status of drugs on the horizon for obesity and the metabolic syndrome - a comprehensive review 2005. IN: Overweight and the Metabolic Syndrome: From Bench to Bedside. New York: Springer Science & Business Media;281-306.
- Bray, G.A. 2006. Surgical treatment of the overweight patient. IN: Overweight and the Metabolic Syndrome: From Bench to Bedside. New York: Springer Science & Business Media:307-327.