Influence of dietary protein level on body composition and energy expenditure in calorically restricted overweight cats

High starch intake favours body weight control in neutered and spayed cats living in homes fed ad libitum

Different starch-to-protein ratios were compared among neutered and spayed domiciled cats. Male and female obese and non-obese cats were fed kibble diets ad libitum for 4 months high in starch (HS (38 % crude protein (CP)): starch 32 %, protein 38 %; DM basis) or high in protein (HP (55 % CP): starch 19 %, protein 55 %) but similar in energy and fat in a crossover design. Physical activity was evaluated using an accelerometer, and body composition (BC), energy expenditure (EE) and water turnover (WT) using the doubly labelled water method. Results were compared in a 2 diet × 2 sex × 2 body condition factorial arrangement. Cats fed the HS (38 % CP) diet maintained a constant body weight, but lean mass (LM) tended to be reduced in female obese but to be increased in male non-obese (P < 0·08) and increased in female non-obese cats (P = 0·01). The HP (55 % CP) diet induced an increase in cat body weight and LM (P < 0·05) without altering BC proportion. EE tended to be higher in males (351 (se 8) kJ/kg0·67/d) than females (330 (se 8) kJ/kg0·67/d; P = 0·06), was unaffected by diet or BC, decreased as age increased (R 2 0·44; P < 0·01) and increased as physical activity increased (R 2 0·58; P < 0·01). WT was higher for the HP (55 % CP) diet (P < 0·01) and increased with EE (R 2 0·65; P < 0·01). The HS (38 % CP) diet favoured body weight control during 4 months of ad libitum feeding. Caution is necessary to balance protein in diets of female obese cats over 5 years, as they may have low energy and food intake, with LM loss.

Description of the fasted serum metabolomic signature of lean and obese cats at maintenance and of obese cats under energy restriction

This study aimed to investigate the serum metabolomic profile of obese and lean cats as well as obese cats before and after energy restriction for weight loss. Thirty cats, 16 obese (body condition score 8 to 9/9) and 14 lean (body condition score 4 to 5/9), were fed a veterinary weight loss food during a 4-week period of weight maintenance (L-MAINT and O-MAINT). The 16 obese cats were then energy restricted by a 60% energy intake reduction with the same food for a 10-week period (O-RESTRICT). Fasted serum metabolites were measured using nuclear magnetic resonance and direct infusion mass spectrometry after the maintenance period for L-MAINT and O-MAINT cats and after the energy restriction period for O-RESTRICT and compared between groups using a two-sided t-test. Obese cats lost 672 g ± 303 g over the 10-week restriction period, representing a weight loss rate of 0.94 ± 0.28% per week. Glycine, l-alanine, l-histidine, l-glutamine, 2-hydroxybutyrate, isobutryric acid, citric acid, creatine, and methanol were greater in O-RESTRICT compared to O-MAINT. There was a greater concentration of long-chain acylcarnitines in O-RESTRICT compared to both O-MAINT and L-MAINT, and greater total amino acids compared to O-MAINT. Glycerol and 3-hydroxybutyric acid were greater in O-MAINT compared to L-MAINT, as were several lysophosphatidylcholines. Thus, energy restriction resulted in increased dispensable amino acids in feline serum which could indicate alterations in amino acid partitioning. An increase in lipolysis was not evident, though greater circulating acylcarnitines were observed, suggesting that fatty acid oxidation rates may have been greater under calorie restriction. More research is needed to elucidate energy metabolism and substrate utilization, specifically fatty acid oxidation and methyl status, during energy restriction in strict carnivorous cats to optimize weight loss.

2021 AAHA Nutrition and Weight Management Guidelines for Dogs and Cats

The guidelines discuss the components of a systematic approach to nutritional management of dogs and cats. A nutritional assessment, including a body condition score and muscle condition score, is a screening evaluation that should ideally be performed at every examination. Individualized nutritional recommendations, based on the nutritional assessment, should be designed to achieve and maintain an appropriate body weight and meet nutritional requirements. Communicating nutritional recommendations to clients is a challenging aspect of nutritional management because pet owners may interpret the practice team's guidance as advocacy for a particular pet food brand or a judgment of the client's ability to properly care for the pet or of the owner's own nutritional status. The guidelines discuss approaches for effective, nonjudgmental communication of dietary recommendations to clients and strategies to increase acceptance of and adherence to veterinary nutrition recommendations. Other pet nutrition topics of current interest include recommendations for particular pet life stages, breeds, and disease conditions; risk factors for nutritional deficiencies and obesity; and considerations for home-prepared diets.

Understanding the Nutritional Needs of Healthy Cats and Those with Diet-Sensitive Conditions

Diets for cats must provide complete nutrition and meet the needs of the individual patient. There is no single diet that is perfect for all cats, and veterinarians must consider the needs of the cat as well as the preferences of the owners when making dietary recommendations. This article focuses on the interface between animal factors and nutritional needs in cats and is divided into 3 sections. Section 1 addresses the dietary needs of healthy cats, including differences among life stages. Section 2 addresses common myths regarding feline nutrition. Section 3 addresses common nutrient-sensitive conditions in cats, including sarcopenia of aging.

Interaction between the amount of dietary protein and the environmental temperature on the expression of browning markers in adipose tissue of rats

Background

A low-protein diet increases the expression and circulating concentration of FGF21. FGF21 stimulates the browning process of WAT by enhancing the expression of UCP1 coupled with an increase in PGC1α. Interestingly, the consumption of a low-protein diet could stimulate WAT differentiation into beige/brite cells by increasing FGF21 expression and Ucp1 mRNA abundance. However, whether the stimulus of a low-protein diet on WAT browning can synergistically interact with another browning stimulus, such as cold exposure, remains elusive.

Results

In the present study, rats were fed 6% (low), 20% (adequate), or 50% (high) dietary protein for 10 days and subsequently exposed to 4 °C for 72 h. Body weight, food intake, and energy expenditure were measured, as well as WAT browning and BAT thermogenesis markers and FGF21 circulating levels. The results showed that during cold exposure, the consumption of a high-protein diet reduced UCP1, TBX1, Cidea, Cd137, and Prdm16 in WAT when compared with the consumption of a low-protein diet. In contrast, at room temperature, a low-protein diet increased the expression of UCP1, Cidea, and Prdm16 associated with an increase in FGF21 expression and circulating levels when compared with a consumption of a high-protein diet. Consequently, the consumption of a low-protein diet increased energy expenditure.

Conclusions

These results indicate that in addition to the environmental temperature, WAT browning is nutritionally modulated by dietary protein, affecting whole-body energy expenditure.

Graphical abstract

Factors associated with overweight cats successfully completing a diet-based weight loss programme: an observational study

BACKGROUND

The most common approach for controlled weight loss in cats is dietary caloric restriction, using a purpose-formulated diet. Most previous studies have only assessed short-term outcomes, and no previous study has examined overall success (i.e. odds of reaching target weight). The aim of this study was to determine the factors associated with overweight cats successfully completing a diet-based weight loss programme to reach target weight.

RESULTS

Sixty-two cats were included, and 28 (45%) completed their weight loss programme. The remaining 34 cats (55%) did not reach target weight, of which 2 (3%) were euthanised for unrelated reasons. Reasons for cats stopping the programme prematurely included inability to contact owner (n = 19), owner requested that the programme be completed prior to reaching target weight (n = 5), the cat developed another illness (n = 3), refusal to comply with requirements for weight management (n = 2), owner illness (n = 2), and personal issues of the owner (n = 1). Multiple logistic regression analysis revealed that rate of weight loss and weight loss required were positively (odds ratio [OR] 157.81, 95% confidence interval [CI] 10.00-2492.67) and negatively (OR 0.89, 95% CI 0.81-0.98) associated with the odds of completing the weight loss programme, respectively.

CONCLUSIONS

Future studies should consider developing better methods of supporting the owners of the most obese cats during weight management, since these cats are least likely to complete reach target weight.

An international multi-centre cohort study of weight loss in overweight cats: Differences in outcome in different geographical locations

Introduction

Feline obesity is a worldwide concern which has recently been formally classified as a disease by the veterinary community. Management involves invoking controlled weight loss by feeding a purpose-formulated food in restricted quantities and altering physical activity. Most weight loss studies conducted in cats have been undertaken in research cat colonies from single geographic locations. The aim of this multi-centre cohort study was to determine the efficacy of a short-term dietary weight loss intervention in overweight pet cats across a range of geographical locations globally.

Materials and methods

A 3-month (median 13 weeks, inter-quartile range [IQR] 12–15 weeks) weight loss programme was conducted at 188 veterinary practices in 22 countries, and involving 730 cats, 413 of which completed the programme and had complete data available. All were fed commercially available dry or wet weight loss diets, and median energy intake was 53 kcal/kg BW^0.711/day. The Royal Canin Ethics Committee approved the study, and owners gave informed consent. Owners completed behavioural questionnaires assessing begging, physical activity and quality of life (QOL). Linear mixed models were used to assess the respective influence of time, age, and initial body condition score (BCS) on weight loss and behavioural observations.

Results

At baseline, median age was 72 months (range 12–200 months) and median BCS was 8 (range 7–9). In all, 402/413 cats (97%) lost weight (mean 10.6±6.3%) during the programme at a rate of 0.8 ±0.50%/week. Based upon owner questionnaires, activity and QOL improved (both P<0.001), while begging behaviour decreased (P<0.001) during weight loss. The main factor influencing percentage weight loss was geographical location (P<0.001), with cats in North America losing less weight (median 7.2%, IQR: 4.4–10.4%) than those in both Europe (10.7%, 6-8-15.4%) and South America (10.0%, 6.2–15.4%). Differences in weight loss were also observed amongst countries (P<0.001), with cats in Argentina, Germany, and Italy losing more weight than cats in the USA, and cats in Germany also losing more weight than cats in Portugal.

Discussion/conclusion

Most of the overweight cats enrolled in this international multi-centre study successfully lost weight. The reason for the differences in percentage weight loss amongst geographical locations requires further study.

Metabolic response to three different diets in lean cats and cats predisposed to overweight

Background

The existence of a genetic predisposition to obesity is commonly recognized in humans and rodents. Recently, a link between genetics and overweight was shown in cats. The goal of this study was to identify the effect of diet composition on plasma levels of glucose, insulin, free fatty acids and triglycerides in cats receiving different diets (high-carbohydrate, high-fat and high-protein diets).

Results

Insulin and leptin concentrations were significantly correlated with phenotype. Insulin levels were lower, whereas leptin levels were higher in cats predisposed to overweight. The other blood parameters were not correlated with phenotype. Intake of the high-carbohydrate diet resulted in higher insulin concentrations compared with the two other diets. Insulin levels were within the values described for non-obese cats in previous studies.

Conclusions

There was no difference in metabolic response between the two groups. As the high-carbohydrate diet led to the highest insulin blood concentrations, it might be useful to avoid such diets in cats predisposed to overweight. In addition, even cats with genetically linked obesity can regain insulin sensitivity after weight loss.