Obesity is defined as an accumulation of body fat, over and above what is required by the animal for optimal functioning.
In cats and dogs, obesity is classed as a chronic incurable disease, and is also known to increase the risk of other health conditions such as joint disease, skin disorders, cardiorespiratory issues and diabetes.
Cats and dogs are classed as overweight when they weigh more than 15% above their ideal weight’ the term “obese” is used when a dog or cat weighs more than 30% above ideal.
Recent data have shown that approximately 50% of dogs and 40% of cats in Britain are currently overweight or obese (Courcier et al, 2010). Up to 20% of dogs under the age of four are already obese.
There are many different reasons why a dog or cat may become overweight or obese. Occasionally, an underlying disease is evident (for example hypothyroidism) and it is therefore essential to perform a full clinical examination at an early stage.
Most cases, however, are the result of over-feeding, lack of exercise, or a combination of the two. In these cases, specially formulated weight-loss diets can be beneficial. They are designed to help achieve a significant reduction in energy intake whilst still ensuring a reasonable food volume and a balanced intake of all the vital nutrients.
Key components of a weight-loss diet include:
- Low fat content. Fat is the most energy-dense nutrient. While carbohydrate and protein provides around 4kcals per gram, every gram of fat in the diet supplies 9kcals.
So a restricted level of fat really helps to reduce the energy density of the diet, meaning that the pet takes in less energy for a given volume of food.
- High protein content. This helps to preserve muscle mass, providing the amino acids required to maintain the muscle tissue and ensuring that as much of the weight lost as possible is fat rather than muscle. This helps to keep the dog fit and active, encouraging them to burn more energy.
Increased levels of protein also help to avoid hunger issues by giving a feeling of fullness after each meal. A high protein formulation also helps to complement the low fat level by effectively reducing available energy further.
Although gram for gram, protein and carbohydrate contain the same amount of energy, the body has to work harder to release the energy from protein, burning energy in the process. So by providing more of the remaining calories through protein rather than carbohydrate, there is less net energy available for the body to use or store.
Finally, because dogs usually find fat-restricted diets less palatable, higher levels of protein help to compensate by improving palatability.
- Fibre. Depending on individual requirements, increased levels of fibre can help too, by influencing dietary energy concentration and appetite control. As fibre is bulky but provides no energy, it is a useful way of “diluting” the energy content of the diet.
Fibre also helps to provide a filling effect, again helping to limit food intake and reduce hunger. The blend of fibre types used is particularly important.
Soluble fibre sources, such as psyllium for example, have very particular benefits for appetite control – they help to slow down gut transit and slow the uptake of glucose from the diet, so dogs feel full for longer.
Insoluble fibres, such as cellulose, provide a bulking effect in the stomach but can limit the absorption of other nutrients so should be used as part of a fibre blend.
- L-carnitine. One of the amino acids (the building blocks of proteins), this nutrient normally acts in the body to facilitate the use of fats for energy, particularly by muscle tissue. So by supplementing Lcarnitine in diets designed for weight loss, we can help support fat metabolism and maintain muscle mass.
- Nutrient balance. Diets formulated specifically for weight loss contain higher levels of certain nutrients so that, even when a pet requires a significant energy restriction in order to lose weight, their intake of vital nutrients can be maintained.
- Joint support. Because obesity is known to affect joint health, weight loss diets are often supplemented with nutrients such as glucosamine, chondroitin and omega 3 fatty acids to help support healthy mobility while dogs lose weight.
- Skin health. Similarly, skin health and coat condition often suffers as a result of obesity so nutrients which can help keep the skin healthy are contained in weight loss diets.
Recommend programme
Ideally, no matter how young or old an animal is, and to avoid obesity developing, it is important to recommend a weight management programme to clients.
This should include a suitable balanced life-stage diet (with food weighed daily), the avoidance of excessive treats, an exercise plan, and regular monitoring of weight and body condition scoring.
However, if an animal is already overweight or obese, consideration of the benefits of a specific weight-loss diet in conjunction with a wider weight-loss plan should be considered.
References
Courcier, E. A., Thomson, R. M., Mellor, D. J. and Yam, P. S. (2010) An epidemiological study of risk factors associated with canine obesity. Journal of Small Animal Practice 51 (7): 362-367.
Courcier, E. A., O’Higgins, R., Mellor, D. J. and Yam, P. S. Prevalence and risk factors of feline obesity in a first opinion practice in Glasgow, Scotland. Jnutournal of feline medicine and surgery 12 (10): 746-753.
