The importance of taste and palatability in carbohydrate-induced
overeating in rats.
Sclafani, Anthony, Francois Lucas, and Karen Ackroff.
Department of Psychology, Brooklyn College and the Graduate School,
The City University of New York, Brooklyn, NY 11210
APStracts 2:0351R, 1995.
The importance of taste and palatability in carbohydrate-induced
overeating in rats. Rats offered a carbohydrate solution (sugar or
polysaccharide) in addition to chow typically overeat and gain
excessive weight. The present study sought to determine if the
palatable taste of these solutions contributes to the overeating
response. Adult female rats were fitted with chronic intragastric
(IG) catheters and given ad libitum access to chow and a drinking
fluid which was paired with IG infusions. For one group (P+S) the
flavored solution was a highly preferred mixture of 2% Polycose and
0.2% saccharin paired with IG infusions of 30% Polycose. For a second
group (SOA), the flavored solution (0.03% sucrose octaacetate) had
unpreferred bitter taste and was paired with IG infusions of 32%
Polycose. Thus, both groups were effectively exposed to the
postingestive effects of 32% Polycose but paired with a palatable
(P+S) or unpalatable (SOA) flavor. A Control group had water to drink
paired with IG water infusions. During the 4-week experimental
period, the P+S group consumed 34% more total energy (chow +
Polycose) and gained more weight than did the SOA and Control groups.
The P+S group also consumed substantially more flavored solution and
more energy as Polycose compared to the SOA group. The SOA group did
not gain reliably more weight than the Control group although their
total energy intake was 13% higher than that of the controls. In a
choice test conducted at the end of the experiment the P+S group
displayed a strong preference (98%) for the Polycose+saccharin
solution over water. In contrast to the Control group, which avoided
the SOA solution relative to water, the SOA group preferred the SOA
solution (71%) confirming prior reports of Polycose-conditioned SOA
preferences. These results demonstrate that palatability has a major
effect on the overeating and obesity produced by carbohydrate
solutions. In the absence of a highly preferred taste, the
postingestive actions of Polycose produce only a small hyperphagic
effect and no excess weight gain.
Received 27 February 1995; accepted in final form 27 November
1995.
APS Manuscript Number R136-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95