Obesity is recognised as a disease in companion animals and over 50 percent of cats in the UK are estimated to be overweight or obese (PDSA, 2018). Obesity has a significant adverse effect on health and welfare, and proactive management by veterinary professionals to increase owner education, address obesity and minimise the likelihood of its potential consequences is important (Box 1). This article focuses on feeding and feeding management in cats to both minimise the likelihood of a cat becoming overweight and help to encourage successful weight loss where cats have become overweight or obese.
Defining “overweight” and “obese”
Several body condition score (BCS) scales have been developed, but a nine-point scale is recommended by the BSAVA and WSAVA and is the most extensively validated one. For a cat, ideal BCS is classed as a score of 5, with each additional unit corresponding to 10 percent over the ideal weight. A score of 6 or 7 (10 to 20 percent overweight) is classed as overweight, whilst a score of 8 or 9 is classified as obese. Recording a BCS regularly is a more accurate way of determining body composition than weight.
If a cat has been identified as overweight or obese and weight management recommendations are made by the veterinarian, they should consider both the diet the pet is on and feeding management. Whilst a purpose-formulated obesity management diet is often recommended by the veterinary professional, there may be less emphasis on feeding management or how to encourage physical activity – particularly in cats where simply increasing the length of the walk or encouraging swimming is not a feasible option. However, by considering cats’ natural feeding behaviours, we can both reduce the risk of obesity and help to more successfully tackle it should it occur.
Nutrient profile of a weight loss diet
Most therapeutic weight loss diets are designed to be increased in protein, low in fat and high in fibre, reducing their caloric density to help lead to effective weight loss and increased satiety. In overweight cats, a gradual weight loss of approximately 1 percent body weight per week should be aimed for, though weight loss is often slower than this. For any cat over a BCS of 7, a therapeutic weight loss diet should be fed. Feeding a maintenance or “light” diet can both lead to potential nutrient deficiencies and unsatisfactory weight loss. The nutrient profile of any diet selected should consider the following (Nestle Purina, 2015):
- Maintenance of lean body weight and loss of excess fat
- Higher protein levels and high protein:calorie ratio has been proven to minimise loss of lean weight and encourage loss of fat during weight loss in cats (Laflamme and Hannah, 2005). Increased protein may also help reduce oxidative stress during weight loss. Appropriate overall caloric restriction, particularly by restricting fat (the most energy-dense nutrient) is important
- Avoidance of any potential nutrient deficiencies in the face of reduced calorie intake
- Using a diet with increased nutrient:calorie ratio is important to ensure the diet provides both complete and balanced nutrition when fed at an amount also compatible to achieve weight loss
- Enhanced satiety to discourage excess consumption
- Increased fibre levels are particularly important to aid satiety. In some cases, this can help to reduce begging behaviour (Saker et al., 2019). Cats have also been shown to voluntarily consume less food when fed a slightly higher protein diet
- Excellent palatability to encourage owner compliance and maintain the important part of the human–animal bond associated with feeding
Considering feline behaviour
Pet cats now have a very different lifestyle to feral cats and their wild ancestors. Rather than hunting for multiple small meals throughout the day, they tend to have a much lower level of physical exercise, may have restricted outdoor access, and tend to have their food provided – often ad lib – rather than having to work for it.
Feral cats and the domesticated cat’s wild ancestors are natural predators and would have spent a large period of time during the day on solitary hunting trips, only half of which would be successful (Dantas et al., 2016). This would have resulted in significant energy expenditure – much more than the domesticated cat’s energy expenditure walking to or from their food bowl. Furthermore, prey caught in the wild tends to have a relatively low energy content. A mouse, for example, may equate to approximately 30 calories. This is in significant contrast to the commercial foods fed now, which, whilst complete and balanced, are also often calorie-dense and highly palatable resulting in a tendency for some cats to overeat.
In addition to this, the majority of domesticated cats are neutered, which can reduce their energy requirements (Root et al., 1996) and can result in increased food consumption from almost immediately after the procedure (Saker et al., 2019). Many cats are also kept in multi-cat households and may be fed together. For some, this can be stressful and result in rapid eating to escape from what is a perceived stressful situation.
All of these aspects should be considered when optimising the home environment and feeding management – both to help limit the likelihood of weight gain and to successfully help achieve weight loss in any overweight cats.
Encouraging “hunting” for food
Wherever possible, encouragement should be made to make cats hunt for their food (Dantas et al., 2016; Saker et al., 2019). This can both increase physical activity and slow down eating. It can also reduce any feelings of guilt that an owner might feel if and when they see their cat’s food bowl is empty.
A range of different feeding enrichment toys and puzzle feeders exist on the market that may require the cat to bat or chase them to release the food and can provide both physical and mental stimulation, helping to increase environmental enrichment whilst providing enjoyment for both the owner and cat (Dantas et al., 2016). Stationary puzzles including foraging toys and mats (Figure 1A), toys requiring sliding, pawing or obstacles (Figure 1B) and rolling puzzles such as balls releasing kibble (Figure 1C and 1D) exist. The toys should be selected according to the owner’s and cat’s preferences.
Toys can also be homemade by members of the family (Figure 2) – a cost-effective and fun option to encourage all members of the family to become involved in any weight loss programme to maximise the likelihood of success and to help increase the bond felt between family members and the pet.
Alterations to the home environment
Alongside delivery of the food, alterations of the home environment to encourage exercise and play can be considered (Saker et al., 2019). Ramps, cat trees and perches may help (Dantas et al., 2016) – and vertical spaces are also naturally liked by many cats. Food can also be hidden in these places to add variety to the location(s) it is offered in. Playing with balls, encouraging cats to chase toy mice (Figure 3) or playing with feathered toys can also increase exercise and stimulation, as well as build a bond between the owner and cat – demonstrating to an owner that there are alternative ways to build bonds with the cat rather than feeding alone (Saker et al., 2019).
Maximising the cat’s “grazer” behaviour
Where feasible, small meals fed little and often can replicate hunting trips in the wild (Saker et al., 2019), may be preferred by many cats and help to increase energy expenditure if cats are encouraged to “work” for their food on a regular basis. Taking an average 25g mouse of approximately 30kcal, a 4kg cat might need to catch eight or nine mice daily to meet their energy requirements. However, this equates to only approximately 8g of an average commercially available dry cat food, or very slightly more than this if feeding an obesity management diet for weight loss. This emphasises the importance of education of what the cat should be being fed, which may be very different to what the owner has previously thought they required, and also highlights that careful food measurement by owners – by weight, not cup estimates – is critical. Feeding such small meals in puzzle feeders rather than a bowl might help to reduce owner concerns that the bowl is empty and they could be underfeeding their cat. It can be worth considering weighing the daily allowance and then potting up for the day, to avoid owners individually weighing each small meal which may be time or labour intensive. If an owner is out all day, automated feeders could be a potential option to enable delivery of multiple small meals and “rations” the cat more effectively if they are home on their own (Saker et al., 2019). This also removes some of the guilt from an owner for feeding less (Saker et al., 2019), as well as reducing potential overeating and/or feelings of frustration in the cat.
Treats are given to cats by 81 percent of owners (PDSA, 2018), and the additional calorie intake this provides can be a contributing factor to obesity. Encouraging the feeding of small, regular meals may also help owners to reduce their need to treat since their cat is being provided with food regularly. However, for some owners treating – and ensuring this is something different to the main meal – remains a key part of the cat–owner bond for them. Sometimes potential bonding alternatives such as grooming or playing may be successful. However, in other cases an owner may be insistent on treating. In such cases, treats may be incorporated into the “grazing” during the day, but the owner must ensure these are removed from the weighed daily allowance. Options such as a prawn, wrapped in foil for the cat to bat around and play with before unwrapping and eating, may be popular with some owners, and raw courgette can also be used in some cats as a low calorie treat.
Considering diet texture
As well as the nutrient profile of the food fed, consideration of the diet’s texture can be important. Wet pouch or canned diets contain significantly more moisture than dry foods, and thus have a lower energy density as-fed. Using wet diets may help increase gastric filling and reduce voluntary energy intake in cats. If wet food isn’t an option, encouraging water intake in other ways may help cats feel satiated, including offering a special treat that includes as much water as possible (Saker et al., 2019). One example would be a prawn.
From an owner’s perspective, choosing a wet diet will result in feeding a greater volume of food, which could potentially increase compliance. Given pouches are often in a “single serve” format, it may make measurement easier for some owners too and reduce the temptation to open another pouch to feed extra food.
For some owners, feeding a combination of wet and dry may be a more preferable, and slightly less expensive, option. However, if this is chosen, it is important they adjust both feeding guides accordingly to account for the fact they are feeding a combination of two foods. Experimentation with flavours and textures to choose a diet which the cat enjoys is important and may help reduce the tendency to treat if the owner can see their pet enjoying the meal.
Taking advantage of cats’ natural instinct to work for their food can both provide environmental enrichment and improve the potential success of any weight management undertaken. Considering how the food is delivered as well as the diet itself can have a significant impact on client compliance as well as encouraging weight loss in cats. It may also have an important prevention role to minimise the likelihood of cats becoming overweight.