Similar fructose increases have been reported in healthy volunteers who consumed fructose loads between 0.5 and 0.75 g / kg34 and in individuals who consumed fructose - sweetened beverages with mixed meals.35 Leptin and ghrelin levels were indistinguishable following acute ingestion of
glucose or fructose, a finding possibly attributable
to the short time interval of observation; leptin levels typically change 4
to 6 hours after
glucose administration.36 Although fructose was previously reported
to be less effective than
glucose in suppressing ghrelin, such differences may be attributable
to the different conditions and timing of ghrelin measurements.10 Little is known about the acute PYY
response to fructose ingestion compared with
glucose ingestion, although 1 study in rats found higher rather than lower PYY levels after 24 hours of
glucose but not fructose feeding.11 Whether such disparities are related
to study design or species differences remains uncertain.
After consuming the U.S. Food and Drug
Administration's maximum dose of saccharin over a period of five days, four of the seven subjects showed a reduced
glucose response in addition
to an abrupt change in their gut microbes.