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Partial weight reduction protocols in cats lead to better weight outcomes, compared with complete protocols, in cats with obesity

German AJ, Woods-Lee GRT, Biourge V, Flanagan J. Partial weight reduction protocols in cats lead to better weight outcomes, compared with complete protocols, in cats with obesity. Front Vet Sci. 2023 Jun 20;10:1211543. doi: 10.3389/fvets.2023.1211543. PMID: 37408831; PMCID: PMC10318927.

Feline obesity is a major issue in cats worldwide. It is a prevalent chronic disease that has negative impacts on both the health and well-being of cats.
This study discusses the two main approaches to weight reduction in cats:
• Complete Weight Reduction: This approach aims for the cat to reach their ideal weight. This method can be challenging as it may require a longer duration of the weight reduction protocol, which can lead to a slower rate of weight loss and reduced compliance.
• Partial Weight Reduction: This approach intentionally plans for the cat to lose only a portion of its excess weight, with the target remaining above the cat’s ideal weight.
This is seen as more achievable, taking weeks rather than months to achieve, and still leads to functional improvements and an improved quality of life, even though the cat remains overweight.
To the authors’ knowledge, there have been no previous studies that compare the differences between complete and partial weight reduction protocols in cats.

Regardless of the chosen weight reduction protocol, weight loss usually involves feeding a therapeutic diet. These diets are specially formulated with increased essential nutrients relative to their energy content to meet the cat’s requirements even when consuming fewer calories than usual. There has been limited research on whether essential nutrient intake is adequate in cats with obesity undergoing controlled weight reduction using therapeutic diets. Two previous studies, have been done but these studies were short-term and didn’t involve significant weight loss.
The primary aim of the current study was to compare outcomes in cats undergoing complete and partial weight reduction protocols. This includes assessing the rate of weight loss and changes in body composition. Additionally, the study aimed to evaluate the adequacy of essential nutrient intake in cats following these protocols and determine if there are any differences between the two approaches.

This study focused on overweight pet cats that underwent a weight reduction program at the Royal Canin Weight Management Clinic in the UK from January 2005 to July 2021. These cats were considered eligible for the study if they had successfully completed their weight reduction program by February 2022 and had no other health issues that could affect their eating habits or nutritional needs.

The study involved two types of weight reduction plans for these cats:
• Complete Weight Reduction: This aimed to bring the cat’s weight within 5% of their ideal weight.
• Partial Weight Reduction: In this plan, the target weight was set intentionally above the ideal weight but still aimed for significant weight loss to improve the cat’s health and well-being.
Reasons for choosing this plan included the cat’s age, marked obesity, or a combination of both.

Before starting the weight reduction program, the cats underwent a thorough health assessment, including physical examinations, blood tests, and body condition assessments. The ideal weight for each cat was determined either by measuring body composition using advanced technology or by assessing body condition scores.
During the weight reduction program, the cats were fed a therapeutic diet designed for weight loss, and owners were given advice on stimulating physical activity. The owners kept a diary to record the cat’s diet, activity levels, and any issues.
Once the cats reached their target weight, they were reassessed using the same health measures, and their body composition was re-evaluated in most cases.
The study also looked at the intake of essential nutrients during the weight loss period and compared it to recommended guidelines. It used statistical analyses to examine differences in various factors between cats undergoing complete and partial weight reduction.

A total of 58 cats were included in the study, with 80% of them undergoing a complete weight reduction program and 20% following a partial weight loss program. The cats in the partial program aimed for a target weight that was greater than their ideal weight by a median of 18%.
There were no significant differences in terms of sex, breed, or starting body weight between cats in the complete and partial weight reduction groups. However, cats in the complete program were generally younger and had lower body fat percentages compared to those in the partial program.
The estimated ideal weight for cats in the complete weight reduction group was greater, and the percentage above ideal weight was less compared to cats in the partial weight reduction group.

Both groups had similar diets, with approximately half of the cats being exclusively fed dry therapeutic diets, while the others had a combination of wet and dry therapeutic diets. There were no differences in the diets used or the number of visits between the two groups.
On average, cats in both groups lost about 23-25% of their starting body weight over a period of around 178-294 days. The rate of weight loss was slower in the complete weight reduction group, and these cats required more visits during their weight loss program.
Cats in the complete weight reduction group had less fat mass and lower fat percentages compared to cats in the partial group both before and after the weight reduction program. Lean mass decreased in cats undergoing complete weight reduction but remained stable in cats following the partial weight reduction program.

When it came to essential nutrient intake during weight reduction, the study found that cats generally consumed more than the recommended amounts of essential nutrients, except for choline, phenylalanine/tyrosine, potassium, and selenium. Many cats had lower intake levels of selenium and choline compared to recommendations. Potassium and phenylalanine/tyrosine intake was marginally lower in some cats.
Importantly, there were no significant differences in nutrient intake between cats in the complete and partial weight reduction groups.

In summary, the study compared cats undergoing different weight reduction protocols and found differences in age, body composition, and outcomes. The researchers also assessed nutrient intake and found that, in general, cats consumed enough nutrients during their weight loss programs, but some nutrients were lower than recommended levels in a substantial number of cats. ~MJK

See Also
German AJ, Ryan VH, German AC, Wood IS, Trayhurn P. Obesity, its associated disorders and the role of inflammatory adipokines in companion animals. Vet J. (2010) 185:4–9. doi: 10.1016/j.tvjl.2010.04.004

German AJ, Holden SL, Bissot T, Morris PJ, Biourge V. Changes in body composition during weight loss in obese client-owned cats: loss of lean tissue mass correlates with overall percentage of weight lost. J Fel Med Surg. (2008) 10:452–9. doi: 10.1016/j.jfms.2008.02.004

Marshall WG, Hazewinkel HA, Mullen D, De Meyer G, Baert K, Carmichael S. The effect of weight loss on lameness in obese dogs with osteoarthritis. Vet Res Commun. (2010) 34:241–53. doi: 10.1007/s11259-010-9348-7