Lifestyle Science: 

Physical activity, diet (energy intake and diet composition), stress and other lifestyle factors may affect morbidity (metabolic diseases, depression, cancer), mortality, and longevity. We have shown that even small amounts of physical activity and small changes in energy intake can increase insulin sensitivity, whereas larger exercise volumes are required to decrease next-day lipemia. Our studies support the notion that exercise, alone or in combination with diet, can acutely improve health in humans. Epidemiologic studies show a significant effect of lifestyle determinants on healthy aging.

  1. Tyrovolas S, Haro JM, Foscolou A, Tyrovola D, Mariolis A, Bountziouka V, Piscopo S, Valacchi G, Anastasiou F, Gotsis E, Metallinos G, Papairakleous N, Polychronopoulos E, Matalas AL, Lionis C, Zeimbekis A, Tur JA, Sidossis LS, Panagiotakos DB; MEDIS Study Group. Anti-Inflammatory Nutrition and Successful Ageing in Elderly Individuals: The Multinational MEDIS Study. Gerontology 2018; 64(1): 3-10.
  2. Tambalis KD, Panagiotakos DB, Moraiti I, Psarra G, Sidossis LS; and the ΕΥΖΗΝ Study Group.Poor dietary habits in Greek schoolchildren are strongly associated with screen time: results from the EYZHN (National Action for Children's Health) Program. Eur J Clin Nutr. 2018 Apr;72(4):572-580. doi: 10.1038/s41430-018-0119-9. Epub 2018 Mar 2.  PMID: 29500462
  3. Foscolou A, Tyrovolas S, Soulis G, Mariolis A, Piscopo S, Valacchi G, Anastasiou F, Lionis C, Zeimbekis A, Tur JA, Bountziouka V, Tyrovola D, Gotsis E, Metallinos G, Matalas AL, Polychronopoulos E, Sidossis LS, Panagiotakos DB. The Impact of the Financial Crisis on Lifestyle Health Determinants Among Older Adults Living in the Mediterranean Region: The Multinational MEDIS Study (2005-2015). J Prev Med Public Health. 2017 Jan;50(1):1-9. PMID: 28173690
  4. Masana MF, Haro JM, Mariolis A, Piscopo S, Valacchi G, Bountziouka V, Anastasiou F, Zeimbekis A, Tyrovola D, Gotsis E, Metallinos G, Polystipioti A, Tur JA, Matalas AL, Lionis C, Polychronopoulos E, Sidossis LS, Tyrovolas S, Panagiotakos DB. Mediterranean diet and depression among older individuals: The multinational MEDIS study. Exp Gerontol. 2018 May 24;110:67-72. doi: 10.1016/j.exger.2018.05.012. [Epub ahead of print]. PMID: 29775747
  5. Bellou, E., A. Siopi, M. Galani, M. Maraki, Y.E. Tsekouras, D.B. Panagiotakos, S.A. Kavouras, F. Magkos, and Sidossis LS. Acute Effects of Exercise and Calorie Restriction on Triglyceride Metabolism in Women. Med Sci Sports Exerc. 2013, 45:455-461
  6. Maraki M, Angelopoulou N, Christodoulou N, Anastasiou CA,Toutouza M, Panagiotakos DB, Kavouras SA, Magkos F, Sidossis LS. Lifestyle intervention leading to moderate weight loss normalizes postprandial triacylglycerolemia despite persisting obesity. Obesity, 2011 May;19(5):968-76
  7. Tsekouras YE, Magkos F, Kellas Y, Basioukas K, Kavouras SA, Sidossis LS. High-intensity interval aerobic training reduces hepatic VLDL-triglyceride secretion rate in men. Am J Physiol Endocrinol Metab 2008;295 (4):E851-E858.
  8. Nassis GP, Papantakou K, Skenderi K, Triantafillopoulou M, Kavouras SA, Yannakoulia M, Chrousos GP, Sidossis LS. Aerobic exercise training improves insulin sensitivity without changes in body weight, body fat, adiponectin and inflammatory markers in overweight and obese girls. Metabolism. 2005;54:1472-1479.

Functional significance of brown fat activation and browning of white fat:

Even though in animal models activation of brown fat prevents diet-induced obesity and normalizes glucose and lipid metabolism, the functional significance of this tissue in humans has not been shown. We presented evidence that brown fat activation increases glucose clearance, insulin sensitivity and plasma FFA oxidation. Further, we have shown the significance of mitochondrial uncoupling on thermoregulation and energy metabolism in burn injury in humans.​

  1. Chondronikola M, Porter C, Malagaris I, Nella AA, Sidossis LS. Brown adipose tissue is associated with systemic concentrations of peptides secreted from the gastrointestinal system and involved in appetite regulation. Eur J Endocrinol. 2017 Jul;177(1):33-40. PMID: 28566533
  2. Chondronikola M, Volpi E, Børsheim E, Porter C, Saraf MK, Annamalai P, Yfanti C, Chao T, Wong D, Shinoda K, Labbe SM, Hurren NM, Cesani F, Kajimura S, Sidossis LS. Brown adipose tissue activation is linked to distinct systemic effects on lipid metabolism in humans. Cell Metab. 2016 May 26 [Epub ahead of print]. PMID: 27238638
  3. Porter C, Herndon DH, Chondronikola M, Chao T, Annamalai P, Bhattarai N, Saraf MK, Capek K, Reidy PT, Daquinag AC, Kolonin MG, Rasmussen BB, Børsheim E, Toliver-Kinskey T, Sidossis LS. Human supraclavicular brown adipose tissue mitochondria have comparable UCP1 function to those found in murine interscapular brown adipose tissue. Cell Metab. 2016 Aug 9;24(2):246-55. PMID: 27508873
  4. Sidossis LS, Porter C, Saraf MK, Børsheim E, Radhakrishnan RS, Chao T, Ali A, Chondronikola M, Mlcak R, Finnerty CC, Hawkins HK, Herndon DN. Browning of Subcutaneous White Adipose Tissue in Humans. Cell Metab. 2015 Aug 4;22(2):219-27

Regulation of VLDL-TG metabolism:

Plasma VLDL-TGs are controlled by the rate of production (by the liver) and the rate of clearance (by peripheral tissues and the liver). We have shown that hepatic VLDL-TG production and secretion are regulated by increased availability of glucose to the liver (i.e. are increased when a person consumes a high carbohydrate diet).  Sex and obesity play a significant role in modulating this response.

  1. Mittendorfer B, Patterson BW, Klein S, Sidossis LS. VLDL-triglyceride kinetics during hyperglycemia-hyperinsulinemia: effects of sex and obesity. Am J Physiol Endocrinol Metab 2003; 284: E708-715.
  2. Mittendorfer B, Sidossis LS. Mechanism for the increase in plasma triacylglycerol concentrations after consumption of short-term, high-carbohydrate diets. Am J Clin Nutr 2001; 73: 892-899.
  3. Sidossis LS, Mittendorfer B, Walser E, Chinkes D, Wolfe RR. Hyperglycemia-induced inhibition of splanchnic fatty acid oxidation increases hepatic triacylglycerol secretion. Am J Physiol 1998; 275(38): E798-E805.
  4. Sidossis LS, Coggan AR, Gastaldelli A, Wolfe RR. Pathway of free fatty acid oxidation in human subjects. Implications for tracer studies. J Clin Invest 1995; 95: 278-284.

Obesity: Epidemiology, prevention and treatment:

Obesity is on the rise, accompanied by metabolic disorders. We have presented evidence that even though childhood obesity rates have stabilized over the last 10 years, the rates of overweight children are alarmingly high. Further, the relationships of physical activity, energy intake, and whole body and abdominal obesity are not straightforward and require detailed research.

  1. Tambalis KD, Panagiotakos DB, Psarra G, Sidossis LS. Current data in Greek children indicate decreasing trends of obesity in the transition from childhood to adolescence; results from the National Action for Children's Health (EYZHN) program. J Prev Med Hyg. 2018 Mar 30;59(1):E36-E47. 2018 PMID: 29938238
  2. Mourtakos SP, Tambalis KD, Panagiotakos DB, Antonogeorgos G, Alexi CD, Georgoulis M, Saade G, Sidossis LS. Association between gestational weight gain and risk of obesity in preadolescence: a longitudinal study (1997-2007) of 5125 children in Greece. J Hum Nutr Diet. 2017 Feb;30(1):51-58. Epub 2016 Jul 14. PMID: 27412890
  3. Tambalis KD, Panagiotakos DB, Kavouras SA, Papoutsakis S, Sidossis LS. Higher prevalence of obesity in Greek children living in rural areas despite increased levels of physical activity. J Paediatr Child Health. 2013 Sep;49(9):769-74
  4. Tambalis KD, Panagiotakos DB, Kavouras SA, Kallistratos AA, Moraiti IP, Douvis SJ, Toutouzas PK, Sidossis LS. Eleven-year Prevalence Trends of Obesity in Greek Children: First Evidence that Prevalence of Obesity is Leveling Off. Obesity (Silver Spring). 2009 Jan;18:161-166.

Metabolic regulation after severe burn injury:

Severe burn injury causes, among other things, significant changes in metabolic control. Hypermetabolism and insulin resistance (hepatic and peripheral) are two of the most commonly observed changes. I have worked in the Shriners Hospital for Children, Metabolism Unit at Galveston for almost 15 years, examining basic and clinical research questions related to burn. In the last few years we are examining the factors responsible for the observed increase in basal metabolic rate after severe burn injury. Our hypothesis is that part of this response is due to increased mitochondrial uncoupling in brown and white adipose tissue and muscle.

  1. Malagaris I, Herndon DN, Polychronopoulou E, Rontoyanni VG, Andersen CR, Suman OE, Porter C, Sidossis LS. Determinants of skeletal muscle protein turnover following severe burn trauma in children. Clin Nutr. 2018 Jun 4. pii: S0261-5614(18)30213-9. [Epub ahead of print]
  2. Porter C, Tompkins RG, Finnerty, CC, Sidossis LS, Suman, OE, Herndon DN. The Metabolic Stress Response to Burn Trauma: Current Understanding and Therapies. The Lancet 2016 Lancet. 2016 Oct 1;388(10052):1417-1426.
  3. Porter C, Herndon DN, Børsheim E, Chao T, Reidy P, Borack M, Rasmussen BB, Chondronikola M, Saraf M, Sidossis LS. Uncoupled skeletal muscle mitochondria contribute to hypermetabolism in severely burned adults. Am J Physiol Endocrinol Metab.  2014 Sep 1;307(5):E462-7. PMID: 25074988
  4. Mittendorfer B, Jeschke MG, Wolf SE, Sidossis LS. Nutritional hepatic steatosis and mortality after burn injury in rats. Clin Nutr 1998; 17(6): 293-299.