scholarly journals Induction of ketosis in rats fed low-carbohydrate, high-fat diets depends on the relative abundance of dietary fat and protein

2011 ◽  
Vol 300 (1) ◽  
pp. E65-E76 ◽  
Author(s):  
Maximilian Bielohuby ◽  
Dominik Menhofer ◽  
Henriette Kirchner ◽  
Barbara J. M. Stoehr ◽  
Timo D. Müller ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Dietary Fat ◽  
Peroxisome Proliferator ◽  
High Fat ◽  
Macronutrient Composition ◽  
Peroxisome Proliferator Activated Receptor ◽  
Low Carbohydrate ◽  
High Fat Diets ◽  
Fat Diets

Low-carbohydrate/high-fat diets (LC-HFDs) in rodent models have been implicated with both weight loss and as a therapeutic approach to treat neurological diseases. LC-HFDs are known to induce ketosis; however, systematic studies analyzing the impact of the macronutrient composition on ketosis induction and weight loss success are lacking. Male Wistar rats were pair-fed for 4 wk either a standard chow diet or one of three different LC-HFDs, which only differed in the relative abundance of fat and protein (percentages of fat/protein in dry matter: LC-75/10; LC-65/20; LC-55/30). We subsequently measured body composition by nuclear magnetic resonance (NMR), analyzed blood chemistry and urine acetone content, evaluated gene expression changes of key ketogenic and gluconeogenic genes, and measured energy expenditure (EE) and locomotor activity (LA) during the first 4 days and after 3 wk on the respective diets. Compared with chow, rats fed with LC-75/10, LC-65/20, and LC-55/30 gained significantly less body weight. Reductions in body weight were mainly due to lower lean body mass and paralleled by significantly increased fat mass. Levels of β-hydroxybutyate were significantly elevated feeding LC-75/10 and LC-65/20 but decreased in parallel to reductions in dietary fat. Acetone was about 16-fold higher with LC-75/10 only ( P < 0.001). In contrast, rats fed with LC-55/30 were not ketotic. Serum fibroblast growth factor-21, hepatic mRNA expression of hydroxymethylglutaryl-CoA-lyase, peroxisome proliferator-activated receptor-γ coactivator-1α, and peroxisome proliferator-activated receptor-γ coactivator-1β were increased with LC-75/10 only. Expression of phospho enolpyruvate carboxykinase and glucose-6-phosphatase was downregulated by 50–70% in LC-HF groups. Furthermore, EE and LA were significantly decreased in all groups fed with LC-HFDs after 3 wk on the diets. In rats, the absence of dietary carbohydrates per se does not induce ketosis. LC-HFDs must be high in fat, but also low in protein contents to be clearly ketogenic. Independent of the macronutrient composition, LC-HFD-induced weight loss is not due to increased EE and LA.

Effects of high-fat diets with different carbohydrate-to-protein ratios on energy homeostasis in rats with impaired brain melanocortin receptor activity

2005 ◽  
Vol 289 (1) ◽  
pp. R156-R163 ◽  
Author(s):  
C. Morens ◽  
M. Keijzer ◽  
K. de Vries ◽  
A. Scheurink ◽  
G. van Dijk
Keyword(s):  
Body Weight ◽  
Energy Homeostasis ◽  
Caloric Intake ◽  
Melanocortin Receptor ◽  
High Fat ◽  
Macronutrient Composition ◽  
Plasma Adiponectin ◽  
High Fat Diets ◽  
Glucose Tolerant ◽  
Fat Diets

Changes in dietary macronutrient composition and/or central nervous system neuronal activity can underlie obesity and disturbed fuel homeostasis. We examined whether switching rats from a diet with high carbohydrate content (HC; i.e., regular chow) to diets with either high fat (HF) or high fat/high protein content at the expense of carbohydrates (LC-HF-HP) causes differential effects on body weight and glucose homeostasis that depend on the integrity of brain melanocortin (MC) signaling. In vehicle-treated rats, switching from HC to either HF or LC-HF-HP feeding caused similar reductions in food intake without alterations in body weight. A reduced caloric intake (−16% in HF and LC-HF-HP groups) required to maintain or increase body weight underlay these effects. Chronic third cerebroventricular infusion of the MC receptor antagonist SHU9119 (0.5 nmol/day) produced obesity and hyperphagia with an increased food efficiency again observed during HF (+19%) and LC-HF-HP (+33%) feeding. In this case, however, HF feeding exaggerated SHU9119-induced hyperphagia and weight gain relative to HC and LC-HF-HP feeding. Relative to vehicle-treated controls, SHU9119 treatment increased plasma insulin (2.8–4 fold), leptin (7.7–15 fold), and adiponectin levels (2.4–3.7 fold), but diet effects were only observed on plasma adiponectin (HC and LC-HF-HP<HF). Finally, SHU9119-treated LC-HF-HP-fed rats were less glucose tolerant than others. Relatively low plasma adiponectin levels likely contributed to this effect. Thus HF feeding amplifies obesity induced by impaired MC signaling, provided that the carbohydrate-to-protein (C/P) ratio is high enough. Reduction of the C/P ratio within a HF diet ameliorates hyperphagia and obesity in rats with impaired MC signaling but aggravates associated disturbances in fuel homeostasis.

Low-carbohydrate high-fat diets in combination with daily exercise in rats: Effects on body weight regulation, body composition and exercise capacity

2012 ◽  
Vol 106 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Samantha J. Caton ◽  
Maximilian Bielohuby ◽  
Yinglong Bai ◽  
Lothar J. Spangler ◽  
Lukas Burget ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Exercise Capacity ◽  
Weight Regulation ◽  
Body Weight Regulation ◽  
High Fat ◽  
Daily Exercise ◽  
Low Carbohydrate ◽  
High Fat Diets ◽  
Fat Diets

scholarly journals Low-carbohydrate High-fat Diets: Regulation of Energy Balance and Body Weight Regain in Rats

Obesity ◽  
2009 ◽  
Vol 17 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Samantha J. Caton ◽  
Bai Yinglong ◽  
Lukas Burget ◽  
Lothar J. Spangler ◽  
Matthias H. Tschöp ◽  
...  
Keyword(s):  
Body Weight ◽  
Energy Balance ◽  
Weight Regain ◽  
High Fat ◽  
Low Carbohydrate ◽  
High Fat Diets ◽  
Fat Diets

Dietary Fat Intake, Supplements, and Weight Loss

2000 ◽  
Vol 25 (6) ◽  
pp. 495-523 ◽  
Author(s):  
David J. Dyck
Keyword(s):  
Weight Loss ◽  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Dietary Fat ◽  
Fat Oxidation ◽  
Fat Content ◽  
High Fat ◽  
Underlying Assumption ◽  
High Fat Diets ◽  
Fat Diets

Although there remains controversy regarding the role of macronutrient balance in the etiology of obesity, the consumption of high-fat diets appears to be strongly implicated in its development. Evidence that fat oxidation does not adjust rapidly to acute increases in dietary fat, as well as a decreased capacity to oxidize fat in the postprandial state in the obese, suggest that diets high in fat may lead to the accumulation of fat stores. Novel data is also presented suggesting that in rodents, high-fat diets may lead to the development of leptin resistance in skeletal muscle and subsequent accumulations of muscle triacylglycerol. Nevertheless, several current fad diets recommend drastically reduced carbohydrate intake, with a concurrent increase in fat content. Such recommendations are based on the underlying assumption that by reducing circulating insulin levels, lipolysis and lipid oxidation will be enhanced and fat storage reduced. Numerous supplements are purported to increase fat oxidation (carnitine, conjugated linoleic acid), increase metabolic rate (ephedrine, pyruvate), or inhibit hepatic lipogenesis (hydroxycitrate). All of these compounds are currently marketed in supplemental form to increase weight loss, but few have actually been shown to be effective in scientific studies. To date, there is little or no evidence supporting that carnitine or hydroxycitrate supplementation are of any value for weight loss in humans. Supplements such as pyruvate have been shown to be effective at high dosages, but there is little mechanistic information to explain its purported effect or data to indicate its effectiveness at lower dosages. Conjugated linoleic acid has been shown to stimulate fat utilization and decrease body fat content in mice but has not been tested in humans. The effects of ephedrine, in conjunction with methylxanthines and aspirin, in humans appears unequivocal but includes various cardiovascular side effects. None of these compounds have been tested for their effectiveness or safety over prolonged periods of time. Key words: carnitine, conjugated linoleic acid, ephedrine, pyruvate, hydroxycitrate

Eisenia bicyclis Inhibits Body Weight Gain and Fat Accumulation Induced by High-Fat Diets in Mice

2010 ◽  
Vol 15 (4) ◽  
pp. 262-266 ◽  
Author(s):  
Won-Hee Choi ◽  
Ji-Yun Ahn ◽  
Sun-A Kim ◽  
Tae-Wan Kim ◽  
Tae-Youl Ha
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Body Weight Gain ◽  
High Fat ◽  
Eisenia Bicyclis ◽  
Fat Accumulation ◽  
High Fat Diets ◽  
Fat Diets

A Systematic Review of Low-Carbohydrate High-Fat Diets: Does the Research Evidence Support Practice?

2018 ◽  
Vol 118 (10) ◽  
pp. A126
Author(s):  
L. Ross ◽  
J. Musial ◽  
R. Hay ◽  
A. Cawte ◽  
D. McDermid ◽  
...  
Keyword(s):  
Systematic Review ◽  
Research Evidence ◽  
High Fat ◽  
Low Carbohydrate ◽  
High Fat Diets ◽  
Fat Diets
Sign in / Sign up

Export Citation Format

Share Document