In the group with 10 volunteers with obesity, some of them are submitted first to the 60 grams of fat plus water solution (meal challenge) and in another time to only water.

Also, in the group with 10 volunteers without obesity, some of them are submitted first to the 60 grams of fat plus water solution (meal challenge) and in another time to only water.

In the same group with 10 volunteers with obesity, some of them are submitted first to only water (control) and in another time to the 60 grams of fat plus water solution (meal challenge).

Also, in the same group with 10 volunteers without obesity, some of them are submitted first to only water (control) and in another time to the 60 grams of fat plus water solution (meal challenge).

A solution composed by 60 grams of fat and water at ambient temperature is administered to each volunteer, being of the with obesity group or the without obesity group, as follow:

• 300 mL final volume of the solution.
• Time of oral ingestion inferior than 2 minutes.
• 60 minutes before the radiopharmaceutical injection.
• 12 hours fasting minimum.

Using 99m technetium ecd radiopharmaceutical, this study aims to detect rCBF differences between SPECT images performed after a meal challenge composed by 60 grams of fat and water and also after a challenge constituted by only water (control), both ingested orally. This approach is performed in a group of 10 people with obesity and also in 10 people without obesity.

This study looks for mean differences of blood levels within and across groups with and without obesity. The metabolites and hormones/cytokines measured are, respectively: glucose and triacylglycerols (measured by spectrophotometry), insulin, leptin, amylin, interleukin 6 (IL-6), tumor necrosis factor alpha, active ghrelin, peptide yy (PYY) and pancreatic polypeptide (PP) (multiplexed assay using luminex).