Abstract
Background
We challenge the current belief that obesity is a result of overnutrition by studying a rodent model of human obesity.
Methods
Male Sprague-Dawley rats at 3 weeks of age were fed with a mixed normal diet of 10% fat and high-fat diet of 60% fat (50:50) for 2 weeks and then turned to 100% high-fat diet until 43 weeks of age. Body weight gain was recorded, and food intake, eating behavior, and metabolic variables were measured by a comprehensive laboratory animal monitoring system. Body composition was determined by dual-energy X-ray absorptiometry. Ghrelin/obestatin-producing A-like cells in the stomach were analyzed by immunohistochemistry.
Results
Rats on high-fat diet were overweight at 9 weeks of age and later became obese characterized by increased body weight and excess fat deposition. There were no obesity-prone, obesity middle tertile, and obesity-resistant subgroups in rats on high-fat diet. The young rats on high-fat diet, even before becoming overweight (i.e., 8 weeks), consumed larger portion of meal (kilocalorie per meal) and ate faster but less frequent than the rats on normal diet. Obese rats had reduced food intake (expressed as gram per 100-g body weight per 24 h), unchanged calorie intake (kilocalorie per 100-g body weight per 24 h), and energy expenditure (kilocalorie per hour per 100-g body weight), and increased number of A-like cells in the stomach.
Conclusion
Large size of meal, but not overnutrition, appears to be responsible for high-fat diet-induced obesity in rats. We propose a consideration that prevention strategies for obesity epidemic should strongly focus on meal size at early childhood and adolescence.
Similar content being viewed by others
References
Maximova K, McGrath JJ, Barnett T, et al. Do you see what I see? Weight status misperception and exposure to obesity among children and adolescents. Int J Obes (Lond). 2008;32:1008–15.
Editorial. Curbing the obesity epidemic. Lancet. 2005;367:1549.
King D. Foresight report on obesity. Lancet. 2007;370:1754.
Michels KB, Willett WC, Graubard BI, et al. A longitudinal study of infant feeding and obesity throughout life course. Int J Obes (Lond). 2007;31:1078–85.
Rice S, McAllister EJ, Dhurandhar NV. Fast food: friendly? Int J Obes (Lond). 2007;31:884–6.
Bray GA, Tartaglia LA. Medicinal strategies in the treatment of morbid obesity. Nature. 2000;404:672–7.
Mun EC, Blackburn GL, Matthews JB. Current status of medical and surgical therapy for obesity. Gastroenterology. 2001;120:669–81.
Solomon C, Dluhy RG. Bariatric surgery—quick fix or long-term solution? N Engl J Med. 2004;351:2751–3.
Wolfe BM, Austrheim-Smith IT, Ghaderi N. Surgical treatment of obesity: pyloric electrical stimulation. Gastroenterology. 2005;128:225–8.
O'Brien PE, McPhail T, Chaston TB, et al. Systematic review of medium-term weight loss after bariatric operations. Obes Surg. 2006;16:1032–40.
Stettler N. Nature and strength of epidemiological evidence for origins of childhood and adulthood obesity in the first year of life. Int J Obes (Lond). 2007;31:1035–43.
Stender S, Dyerberg J, Astrup A. Fast food: unfriendly and unhealthy. Int J Obes (Lond). 2007;31:887–90.
Speakman J, Hambly C, Mitchell S, et al. Animal models of obesity. Obes Rev. 2007;8(Suppl 1):55–61.
Buettner R, Schölmerich J, Bollheimer LC. High-fat diets: modeling the metabolic disorders of human obesity in rodents. Obesity (Silver Spring). 2007;15:798–808.
Stenström B, Furnes MW, Tømmerås K, et al. Mechanism of gastric bypass-induced body weight loss: one-year follow-up after micro-gastric bypass in rats. J Gastrointest Surg. 2006;10:1384–91.
Furnes MW, Tømmerås K, Arum CJ, et al. Gastric bypass surgery causes body weight loss without reducing food intake in rats. Obes Surg. 2008;18:415–22.
Furnes MW, Stenström B, Tømmerås K, et al. Feeding behavior in rats subjected to gastrectomy or gastric bypass surgery. Eur Surg Res. 2008;40:279–88.
Varma M, Chai JK, Meguid MM, et al. Effect of estradiol and progesterone on daily rhythm in food intake and feeding patterns in Fischer rats. Physiol Behav. 1999;68:99–107.
Levin BE, Triscari J, Hogan S, et al. Resistance to diet-induced obesity: food intake, pancreatic sympathetic tone, and insulin. Am J Physiol. 1987;252:R471–8.
Levin BE, Richard D, Michel C, et al. Differential stress responsivity in diet-induced obese and resistant rats. Am J Physiol Regul Integr Comp Physiol. 2000;279:R1357–64.
Chang S, Graham B, Yakubu F, et al. Metabolic differences between obesity-prone and obesity-resistant rats. Am J Physiol. 1990;259:R1103–10.
Pagliassotti MJ, Knobel SM, Shahrokhi KA, et al. Time course of adaptation to a high-fat diet in obesity-resistant and obesity-prone rats. Am J Physiol. 1994;267:R659–64.
Zorrilla EP, Inoue K, Fekete EM, et al. Measuring meals: structure of prandial food and water intake of rats. Am J Physiol Regul Integr Comp Physiol. 2005;288:R1450–67.
Zhao CM, Furnes MW, Stenström B, et al. Characterization of obestatin- and ghrelin-producing cells in the gastrointestinal tract and pancreas of rats: an immunohistochemical and electron-microscopic study. Cell Tissue Res. 2008;331:575–87.
Archer ZA, Rayner DV, Rozman J, et al. Normal distribution of body weight gain in male Sprague-Dawley rats fed a high-energy diet. Obes Res. 2003;11:1376–83.
Archer ZA, Corneloup J, Rayner DV, et al. Solid and liquid obesogenic diets induce obesity and counter-regulatory changes in hypothalamic gene expression in juvenile Sprague-Dawley rats. J Nutr. 2007;137:1483–90.
Elder KA, Wolfe BM. Bariatric surgery: a review of procedures and outcomes. Gastroenterology. 2007;132:2253–71.
Editorial: Time to supersize control efforts of obesity. Lancet. 2007; 370:1521
Cohen D, Farley TA. Eating as an automatic behavior. Prev Chronic Dis. 2008;5:1–7.
Berg C, Lappas G, Wolk A, et al. Eating patterns and portion size associated with obesity in a Swedish population. Appetite. 2009;52:21–6.
Acknowledgements
We thank Karin Tømmerås (Ph.D.) and Carl-Jørgen Arum (MD) for valuable discussions, Endre Andersen (Ph.D.) for statistical advice, and Trine Skoglund for technical assistance in measuring the serum ghrelin and obestatin concentrations at the Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology. We also thank Morten Grønli and Erik Langørgen at the Department of Energy and Process Engineering for providing bomb calorimeter. This study was supported by grants from the Research Council of Norway and St. Olavs’ Hospital Foundation for Cancer Research. Marianne W. Furnes received a short-term Ph.D. stipend from the Department of Cancer Research and Molecular Medicine.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Furnes, M.W., Zhao, CM. & Chen, D. Development of Obesity is Associated with Increased Calories per Meal Rather than per Day. A Study of High-Fat Diet-Induced Obesity in Young Rats. OBES SURG 19, 1430–1438 (2009). https://doi.org/10.1007/s11695-009-9863-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11695-009-9863-1