title: Low-carbohydrate diets affect energy balance and fuel homeostasis differentially in lean and obese rats.
abstract: In parallel with increased prevalence of overweight people in affluent societies are individuals trying to lose weight, often using low-carbohydrate diets. Nevertheless, long-term metabolic consequences of those diets, usually high in (saturated) fat, remain unclear. Therefore, we investigated long-term effects of high-fat diets with different carbohydrate/protein ratios on energy balance and fuel homeostasis in obese (fa/fa) Zucker and lean Wistar rats. Animals were fed high-carbohydrate (HC), high-fat (HsF), or low-carbohydrate, high-fat, high-protein (LC-HsF-HP) diets for 60 days. Both lines fed the LC-HsF-HP diet displayed reduced energy intake compared with those fed the HsF diet (Zucker, -3.7%) or the HC diet (Wistar rats, -12.4%). This was not associated with lower weight gain relative to HC fed rats, because of increased food efficiencies in each line fed HsF and particularly LC-HsF-HP food. Zucker rats were less glucose tolerant than Wistar rats. Lowest glucose tolerances were found in HsF and particularly in LC-HsF-HP-fed animals irrespective of line, but this paralleled reduced plasma adiponectin levels, elevated plasma resistin levels, higher retroperitoneal fat masses, and reduced insulin sensitivity (indexed by insulin-induced hypoglycemia) only in Wistar rats. In Zucker rats, however, improved insulin responses during glucose tolerance testing and tendency toward increased insulin sensitivities were observed with HsF or LC-HsF-HP feeding relative to HC feeding. Thus, despite adverse consequences of LC-HsF diets on blood glucose homeostasis, principal differences exist in the underlying hormonal regulatory mechanisms, which could have benefits for B-cell functioning and insulin action in the obese state but not in the lean state.
authors.affiliation: Department of Neuroendocrinology, Center for Behavior and Neurosciences, University of Groningen, 9750 AA Haren, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Morens
authors.forename: V
authors.initials: V
authors.lastname: Sirot
authors.forename: A J W
authors.initials: AJ
authors.lastname: Scheurink
authors.forename: G
authors.initials: G
authors.lastname: van Dijk
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001835:Body Weight; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D004435:Eating; D002149:Energy Intake; D004734:Energy Metabolism; D006706:Homeostasis; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D011924:Rats, Zucker; D013851:Thinness / Q000503:physiopathology*
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins