Fat intake affects adiposity, comorbidity factors, and energy metabolism of sprague-dawley rats.
OBJECTIVE
Childhood obesity is an emerging health problem. This study assesses the effects of three levels of dietary fat (10%, 32%, and 45% measured by kilocalories) on weight gain, body composition, energy metabolism, and comorbidity factors in rats from weaning through maturation.


METHODS
The role of dietary fat on the susceptibility to obesity was assessed by feeding diets containing three levels of dietary fat to rats from weaning through 7 months of age. Body composition was analyzed by DXA after 6 and 12 weeks of dietary treatment. Energy metabolism was measured by indirect calorimetry.


RESULTS
Energy intake, weight gain, fat mass, and plasma glucose, cholesterol, triglyceride, free fatty acid, leptin, and insulin levels increased dose-dependently with increased dietary fat. No difference in absolute lean mass among the three groups was observed. Therefore, the differences in weight gain are accounted for primarily by increased fat accretion. Compared with rats that were relatively resistant to obesity when on a 45% fat diet, diet-induced obesity-prone rats were in positive energy balance and had an elevated respiratory quotient, indicating a switch in energy substrate use from fat to carbohydrate, which promotes body-fat accretion.


CONCLUSIONS
Our data support the hypothesis that administration of increasing amount of dietary fat to very young rats enhances susceptibility to diet-induced obesity and its comorbidities.
Ghibaudi
Lorraine
L
Schering-Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
Cook
John
J
Farley
Constance
C
van Heek
Margaret
M
Hwa
Joyce J
JJ
D000273:Adipose Tissue; D000375:Aging; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D002784:Cholesterol / Q000097:blood; D004041:Dietary Fats / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008297:Male; D009765:Obesity / Q000209:etiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014280:Triglycerides / Q000097:blood; D014886:Weaning; D015430:Weight Gain
D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D020738:Leptin; D014280:Triglycerides; D002784:Cholesterol