The purpose of the trial is to assess whether the beneficial effect of liraglutide on weight
is mediated by changes in the composition of the intestinal Microbiome. The main mechanisms
of action of liraglutide were traced to a reduction in the secretion of glucagon and slowing
gastric emptying resulting in decreased appetite and body weight. It also seems that
liraglutide is capable of increasing the satiety signals thanks to a dual mechanism of
stimulation and inhibition induced by medication. Pomc neurons (opiomelacortin) present in
hypothalamic arcuate nuclei, stimulated by liraglutide, glucagon-like peptide- 1 (GLP-1)
receptor expressed by inhibiting intensely appetite. At the same time through the GABAergic
neuronal activity is inhibited neuropeptide Y(NPY) deputies to the production of orexins that
are powerful promoters of appetite. Alterations in the composition of the human gut
microbiome occur in metabolic disorders such as obesity, diabetes. Liraglutide has been
reported to switch microbiome composition towards lean-related bacterial phylotypes in animal
studies. This leads to hypothesize that the switch of microbiome by liraglutide may be one of
the mechanisms through which liraglutide may exert its effect. In particular the
investigators hypothesize that liraglutide could restore a healthy microbiome or at least
improve the microbiome composition through slowing gastrointestinal motility. Moreover, the
liraglutide-related change of microbiome could be an additional mechanism that contribute to
the beneficial metabolic effect of liraglutide. To test this hypothesis the investigators
will investigate if there will be any change of gut microbiome assessed as
Firmicutes-to-Bacteroidetes ratio after liraglutide treatment. In order to understand if the
change of gut microbiome after liraglutide treatment occurs as an association or contributes
to the effect of liraglutide ,the investigators will correlate the
Firmicutes-to-Bacteroidetes ratios with the changes of Body Mass Index, Body Composition,
appetite parameters, chronic inflammation parameters, lipid profile and insulin resistance.
All the subjects will follow the same diet in order to avoid any bias.