Inadequate compliance of owners is a major problem in the prevention and treatment of canine obesity. Warnings on possible health risks of obesity are often disregarded, and owners argue that they love their pet so much that they just cannot deny it treats in the form of food. To find an adequate psychological approach for practitioners in nutrition consultation, we investigated the human-animal relationship, the feeding and care of the dogs and certain personal characteristics (such as eating and health behavior) of 60 owners of obese dogs in comparison with 60 owners of normal dogs.

A large percentage of cats enrolled in clinical trials using weight-reducing diets do not complete the study (1). Epidemiological data indicate that only a small percentage of cats fed reducing diets actually lose weight (2). However, in controlled laboratory trials weight reduction has been achieved by food restriction (3,4), which indicates lack of compliance by owners of cats in weight reducing programs. Psychological approaches, such as substituting a behavior associated with feeding with a nonfeeding behavior may improve compliance of owners of cats participating in weight reduction programs. The basis for such approaches could come from studies on the relationship of humans with their pets (5).

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.

Low-carbohydrate, high-fat (LC-HF) diets are popular for inducing weight loss in adults and are also used as part of a treatment for children with epilepsy. However, potential risks and side effects remain controversial. We investigated effects of LC-HF diets on growth, bone mineral density (BMD), and turnover in growing rats fed for 4 weeks either normal chow (CH, 9% fat, 33% protein, and 58% carbohydrates), LC-HF-1 (66% fat, 33% protein, and 1% carbohydrates), or LC-HF-2 (94.5% fat, 4.2% protein, and 1.3% carbohydrates). Rats fed LC-HF diets accumulated significantly more visceral and bone marrow fat and showed increased leptin but decreased insulin-like growth-factor 1 (IGF-1). Both LC-HF diets significantly decreased body length (nose to rump), but lengths of humerus, tibia, and femur were significantly reduced with LC-HF-2 only. Peripheral quantitative computed tomography (pQCT) and micro-CT (µCT) independently revealed significant reductions in BMD of tibiae in both LC-HF groups, and tibial maximum load was impaired. Bone-formation marker N-terminal propeptide of type I procollagen was reduced in sera of LC-HF groups, whereas bone resorption marker CrossLaps remained unchanged. Real-time PCR analysis revealed significant reductions by 70% to 80% of transcription factors influencing osteoblastogenesis (Runx2, osterix, and C/EBPβ) in bone marrow of rats fed LC-HF diets. In conclusion, both LC-HF diets impaired longitudinal growth, BMD, and mechanical properties, possibly mediated by reductions in circulating IGF-1. Serum bone-formation markers as well as expression of transcription factors influencing osteoblastogenesis were reduced. This might indicate a lower rate of mesenchymal stem cells differentiating into osteoblasts, thus explaining reduced bone formation with LC-HF diets. © 2010 American Society for Bone and Mineral Research

The aim of the present study was to evaluate the vitamin and mineral content of bone and raw food rations fed to adult dogs in Germany. Pet owners completed a standardised feeding questionnaire. The composition of 95 rations was calculated from mean data for foodstuffs using nutrition balancing software. Typical ration ingredients were meats, fish, offal, dairy products, eggs, oil, nuts, cod liver oil and natural and commercial supplements. The supply of nutrients was compared with the recommended allowance (RA). Of the rations that were used, 10 % supplied < 25 % of the RA of Ca. In these rations, Ca:P was below 0·6:1, and vitamin D was below RA. About half of the rations supplied less iodine than the minimum requirement. Many of the rations had low Zn and Cu supply, and 25 % of the rations supplied only 70 % of RA for vitamin A or less. A total of 60 % of the rations had one or more of the above-mentioned imbalance. The remaining 40 % of rations either had minor problems like Ca excess from bones or they were balanced.