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24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

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Human Nutrition Unit

Zone de texte éditable et éditée et rééditée

Christelle GUILLET, PhD


Email : contact
Tel : +33(0)4 73 60 82 58

Christelle Guillet

Many pathophysiological conditions (aging, obesity and other chronic diseases) are associated with muscle alterations. Depending on the circumstances, these impairments are related to both muscle mass and function and have for consequences a reduction in the mobility of people which can affect their quality of life and health. Thus, identification of factors responsible for these muscular alterations is necessary to define ways to maintain muscle mass and function in order to maintain the health and quality of life of elderly or patients with chronic diseases. Among the mechanisms involved in the loss of muscle mass and function, a postprandial anabolic resistance of muscle protein metabolism has been well demonstrated in old animals and elderly. This anabolic resistance is related in part to the development of insulin resistance frequently observed during aging. In a more general concept, insulin resistance seen in many clinical settings, could be seen as a contributor to muscle wasting.

Research Activities

Evolution of muscle mass and muscle protein metabolism in obesity: effect of exercise and lipid restriction.

The establishment of obesity in rats fed a high fat and high calorie diet is done in two phases: a dynamic phase of weight gain during the first 16 weeks of diet, during which muscle mass increases, then a phase static, from 16 to 24 weeks of diet, during which the weight stabilizes and muscle mass diminishes. During the weight gain phase, the muscle protein synthesis rate increases in glycolytic muscles. By contrast, during the weight stable phase, the rate of muscle protein synthesis decreases in these muscles. The changes observed in the glycolytic muscles during the static phase of obesity are associated with significant accumulation of intramuscular lipid. The second part of this study highlighted that after a period of obesity, practice an exercise in endurance combined with a fat balanced diet is associated with a significant weight loss if the exercise or diet are followed alone. Furthermore, this strategy also appears to be beneficial for the muscles because it improves muscle protein metabolism and changes induced by obesity.

The mass and quality of skeletal muscles are affected differently during the development of obesity and during the weight loss. Biochemical and molecular mechanisms involved in these changes remain to be demonstrated in order to identify effective nutritional or therapeutic strategies to limit the quantitative and qualitative loss of muscles especially during very restrictive diets and / or surgical treatment of obesity.


  • Guillet C, Masgrau A, Walrand S, Boirie Y. Impaired protein metabolism: interlinks between obesity, insulin resistance and inflammation. Obes Rev. 2012 Dec;13 Suppl 2:51-7.
  • Masgrau A, Mishellany-Dutour A, Murakami H, Beaufrère AM, Walrand S, Giraudet C, Migné C, Gerbaix M, Metz L, Courteix D, Guillet C, Boirie Y. Time-course changes of muscle protein synthesis associated with obesity-induced lipotoxicity. J Physiol. 2012 Oct 15;590(Pt 20):5199-210.
  • Guillet C, Delcourt I, Rance M, Giraudet C, Walrand S, Bedu M, Duche P, Boirie Y. Changes in basal and insulin and amino acid response of whole body and skeletal muscle proteins in obese men. 2009. J Clin Endocrinol Metab. 94(8):3044-50.
  • Guillet C, Zangarelli A, Gachon P, Morio B, Giraudet C, Rousset P, Boirie Y. Whole body protein breakdown is less inhibited by insulin, but still responsive to amino acid, in nondiabetic elderly subjects. 2004. J Clin Endocrinol Metab. 89(12):6017-24.
  • Guillet C, Prod'homme M, Balage M, Gachon P, Giraudet C, Morin L, Grizard J, Boirie Y. Impaired anabolic response of muscle protein synthesis is associated with S6K1 dysregulation in elderly humans. 2004. FASEB J. 18(13):1586-7.

Curriculum Vitae

2005-2006 : Post-doctorat : Karolinska Institute. Stockholm. Suède
2003-2005 : Attaché Temporaire d'Enseignement et de Recherche. Unité du Métabolisme Protéino-Energétique UMR 1019 INRA-Université d’Auvergne / Institut Universitaire de Technologie –Université d’Auvergne
2003 : Doctorat d'université en nutrition. Unité du Métabolisme Protéino-Energétique UMR 1019 INRA-Université d’Auvergne. Clermont-Ferrand
Activités d'enseignement :
UFR Médecine et Pharmacie, Université d'Auvergne, Clermont-Fd. Deuxième année du Diplôme de Formation Générale en Sciences Médicales (DFGSM2), 3 ème année de Licence Sciences, Technologies, Santé mention Sciences pour la santé parcours Nutrition, Master Sciences, Technologies, Santé mention Nutrition, Santé, Aliments, Diplôme Inter-Universitaire Nutrition et Activité Physique, Diplôme Universitaire Nutrition, Agression, Maladies Chroniques.
Activités de recherche :
Prix de recherche ESPEN (2015-2017 : responsable scientifique) : Impact of different protein levels intake on muscle mass and function in sarcopenic obese rats
Projet financé par la société Lactalis (2012-2014 : collaborateur scientifique) : Effet de la qualité des protéines alimentaires sur la fonctionnalité musculaire après une immobilisation chez le rat adulte et âgé.
Programme hospitalier de recherche clinique (2009-2012 : collaborateur scientifique) : Besoin protéique et intérêt des « protéines rapides » chez le sujet obèse opéré pour chirurgie bariatrique (BIBOP)
Projet financé par la Fondation Cœur et Artères (2008-2011 : partenaire) : Effet de l’activité physique et d’une diète sur le traitement du syndrome métabolique chez l’homme et chez le rat
Programme Hospitalier de Recherche Clinique (2007-2008 : collaborateur scientifique) : Impact de la stimulation cérébrale profonde du noyau sous-thalamique sur la production hépatique de glucose dans la maladie de Parkinson.