[Analysis of gastric emptying dynamics in relationship to qualitative composition of intake. Comparison between normal-weight and obese subjects].

AIMS

To analyze whether the gastric emptying profile could define obesity and to study the impact of macronutrients diet composition on gastric emptying in obese and non obese people.

MATERIAL AND METHODS

47 subjects were selected (12 non obese and 35 obese). The study was organized in 4 visits. In each visit the subject was given isocaloric breakfast differing in macronutrient composition, (either equilibrated, or lipid, protein or carbohydrate rich) quantitative gastric emptying assay was done realized, every 15 minutes for two hours using a radionuclide technique. The week prior to the visit, the subject followed a standard 1,800 cal/day diet.

RESULT

A significant interaction between time and diet composition is shown regardless of the group (obese or non-obese) the subject belongs to. The different macronutrient composition differentially affected gastric emptying only in the obese group. Post hoc analysis of the results showed significant differences after 45 min post breakfast between protein and carbohydrate rich breakfast.

CONCLUSIONS

Gastric emptying in obese but not in non obese subjects, was significantly modified depending on the intake qualitative composition. These differences are clear when protein rich (significantly slower emptying) is compared versus hydrocarbon enriched diet (significantly faster emptying). A significant difference in gastric emptying between obese and non-obese subjects cannot be established.