Weightloss

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Weight Loss

Weight loss through diet and exercise is the most common and effective means of losing weight, however, it may be easier said than done as many factors must be considered, and it is not as simple as just feeding the dog a smaller serving of their normal food and exercising more as this may lead onto other problems.

The Importance of Protein

Dogs require a relatively high proportion of protein in their diet, approximately 20% (Fleeman, 2006). Older dogs require higher levels of protein to maintain nitrogen balance and to maximise their protein reserves (Laflamme, review). This is especially important to note, as this is also the patient group which is most prone to developing OA. On the other hand, they also have lower calorific needs. Weight loss can only be achieved through negatively balanced energy expenditure, i.e. calorie intake is less than total amount of energy requirement and expenditure. If the normal food is given in smaller amounts, proportion of protein may well fall below minimum requirement, and thus cause loss of lean body mass. Lean body mass, or fat free mass (FFM) as it is often referred to, is the proportion of the body that consist of core structures and organs such as the skeleton, muscles, skin, coat, nervous system, circulatory and respiratory system, and internal organs. It is never a goal to loose any of the lean body mass, but this can happen and quite quickly if protein containing essential amino acids is insufficiently supplied. The body can manufacture its own non-essential amino acids, but not essential ones which have to be provided in the diet. Lean body mass determines an animals resting energy requirement (RER). Consequently, if the lean body mass decreases, so will the dogs RER. Another important note is that maintenance energy requirement (MER) is highly variable, and dependant on several factors such as; breed (hereditary proneness, gender (F>M), neutering status, activity level (work, size of yard, companion, amount of exercise) and age.

Protein is very important to the diet. The dogs body is made up from 50% protein (dry weight), and amino acids are crucial in maintenance, health and growth of the bodies tissues. Protein, broken down to amino acids, is used to produce enzymes, hormones and blood proteins, which are crucial to bodily functions such as digestion and absorption of nutrients, metabolism, regulation of glucose, and the immune system. Amino acids are also crucial in the synthesis of tissue protein, especially in relation to growth and healing, and are also a primary fuel for producing energy. The body also continuously breaks down and manufactures new body proteins, a process known as protein turnover, which obviously can only be done if there are available amino acids. Dietary protein deficiency reduces the protein turnover, and may thus affect any or all of the functions of the body that is dependant on amino acids, dictating the overall health of the animal.

From a physiotherapist’s perspective, primarily concerned with the musculoskeletal system, sufficient levels of highly digestible protein in the patient’s diet is of upmost importance. Physiotherapists ask the body to produce more work and gain strength, and often; tissues are also healing. Neither is possible unless protein intake is adequate. A dog’s body will simply not be able to provide the needed amino acids to build muscle bulk, if sufficient levels to do so are not present. Adipose tissue can provide fuel for energy, and therefore can be lowered in the diet, to promote utilisation of this. Similarly, intake of carbohydrates can be reduced, to encourage burning of body fat. To make up lost bulk of food, indigestible fibre is added to the diet so that the dog gains a sense of satiety, and is not left wanting for more. When reducing the calorie intake through adjusting a dog’s diet, the minimum requirement of RER is sought. Several authors report diet restriction as a percentage of MER, however, one must take care to maintain optimal nutrition, and aiming towards at least covering the animals RER seems the most appropriate. It may be wise to increase to proportion of protein to above 20%, as a physiotherapist will seek to also increase the lean body mass through work, and also take into account that healing needs to be optimised. Increasing the lean body mass will increase the basal metabolism, and therefore aid weight loss, in addition to priming the body’s capacities for the load it is carrying.

Hannah and Laflamme (1998) studied weight loss and loss of lean body mass with three dietary protein levels (20%, 30% and 39% of calories). They found that the group given 20% lost approximately twice the amount of lean body mass as the other two groups did, indicating that 20% is too low a level when on a calorie restricted diet, as much of the weight lost is of the lean body mass. Diez et al. (2002) found similar on their test groups, which were given 23.8% and 47.5%. Weight loss was greater in the lower protein group, but loss of lean body mass was also greater. Wakshlag et al. (2003) studied effects of protein ratios on normal dogs, and found that the group fed a 12% protein diet over 10 weeks had a significant loss of lean body mass and increased levels of fat mass. There were no alterations in the group fed 28% protein, despite same amount of calories fed. There were also no differences in weight, or body scoring for either group, before or after the study. This illustrates that it may not be evident from examination alone that a dog is protein deficient, as it may present a healthy. Yoo et al. (2006) found no difference between RER or change in body composition in groups of dogs fed a weight maintenance diet either high or low in fat. Both diets contained > 20 % protein, which may explain why there was no change seen. Blanchard et al. (2004) confirms that a low calorie food, with a high protein: energy ratio facilitates rapid weight loss whilst preserving lean body mass. They fed obese Beagles at 50% of MER, on a commercial, nutritionally balanced weight-loss food containing 26% protein.

It is clear that in order to loose weight effectively and safely, nutritional needs have to be met. Many people like to prepare the food for their dog themselves, but there are several disadvantages with this, as the food may not be nutritionally complete or balanced and it may end up like an advanced science project if it is to be done well. It might be time, cost and labour saving to simply purchase a quality purpose-specific commercial food from a reputable seller, such as a veterinary clinic. Many veterinary practices have weight loss clubs/classes these days and this is probably a good environment for owners of obese or overweight dogs to attend for education and feedback.

Treating the Overweight and Arthritic Canine Patient

An overweight dog suffering from osteoarthritis will have painful joints, exacerbated by the excessive weight he is carrying, and higher weight bearing activities such as jumping and running. He is likely to be lethargic and in a state of poor physical fitness, and have reduced ROM, as end range demands more muscle work and has a tendency to be sore. Tough love and heavy exercise is not the humane way to go about this. Contact your Veterinarian or Animal Physiotherapist for weight loss advice.

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References

Blanchard G, Nguyen P, Gayet C, Leriche I, Siliart B and Paragon BM (2004) Rapid Weight Loss with a high-protein low-energy diet allows the recovery of ideal body composition and insulin sensitivity in obese dogs. Journal of Nutrition 134, pp 2148-2150

Diez M, Nguyen P, Jeusette I, Devois C, Istasse L, Biourge V (2002) Weight loss in obese dogs: evaluation of a high-protein, low-carbohydrate diet. Journal of Nutrition. 132(6 Suppl 2), pp 1685-1686

Fleeman L (2006) Canine and equine nutrition. In “ANIM 7112 Husbandry of Companion and Competition Animals.” (University of Queensland, Australia)

Laflamme DP (2005) Nutrition for aging cats and dogs and the importance of body condition. Veterinary Clinics of North America - Small Animal Practice. 35(3) pp 713-742

Wakshlag JJ, Barr SC, Ordway GA, Kallfelz FA, Flaherty CE, Christensen BW, Shepard LA, Nydam DV, Davenport GM (2003) Effect of dietary protein on lean body wasting in dogs: correlation between loss of lean mass and markers of proteasome-dependent proteolysis.
Journal of Animal Physiology and Animal Nutrition. 87(11-12), pp 408-420

Yoo S, Ramsey JJ, Havel PJ, Jones PG, Fascetti AJ (2006) Resting energy expenditure and body composition of Labrador Retrievers fed high fat and low fat diets. Journal of Animal Physiology and Animal Nutrition. 90(5-6), pp 185-191

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