Defense of a lowered weight maintenance level by lateral hypothamically lesioned rats: Evidence from a restriction-refeeding regimen

Male rats maintained their body weight at approximately 85% that of sham-lesioned controls following lesions of the lateral hypothalamus (LH). One month following surgery, the food intake of half the LH-lesioned animals was restricted until their body weight had declined to 80% that of nonrestricted LH animals. Half the sham-lesioned animals were similarly restricted until their body weight fell to 80% that of nonrestricted control animals. When returned to an ad lib feeding schedule, both restricted groups were initially hyperphagic and quickly restored their body weights to the level of the nonrestricted group from which they were originally selected. In doing so, the LH animals increased their food intake by the same amount and took the same number of days to restore their weight to control levels as the sham-lesioned animals. These observations provide further evidence of the vigor and effectiveness with which LH animals defend their reduced level of maintained body weight.