Information on Appropriate Weight in Dogs

Why  keep your dog thin? We put together excerpts from some of our favorite sources on this subject. At the bottom we include a list of articles that may also be of interest. The short answer is that if a dog is being fed a balanced diet that contains everything that is needed for optimal health, reducing the number of calories so that the dog stays very lean has numerous benefits and virtually no drawbacks.  A staggering number of dogs have obesity related illness, thin but well nourished dogs live longer, healthier, happier lives!! If people think your dog is too thin, you probably have a healthy dog!  If you are not sure, discuss it with a skilled veterinarian.

Gene Expression Profile of Aging and Its Retardation by Caloric Restriction

Cheol-Koo Lee, Roger G. Klopp, Richard Weindruch,  Tomas A. Prolla

Summary of Study--

Tomas A. Prolla and Richard Weindruch, both of the University of Wisconsin, Madison, said their genetic analysis of mice showed that genes that normally deteriorate with age tended to continue functioning in a youthful way when the mice were underfed.

 They said the study, to be published in the journal Science on Friday, may explain why a reduced-calorie diet can cause mice to live up to 50% longer.

  There have been studies in monkeys that show a low calorie diet does lower blood pressure and raise levels of ''good'' cholesterol, both signs of improved health that suggest a longer life. Those studies, however, did not examine the fundamental genetic changes that occur as a part of the aging process.

 ''This study is quite important because it breaks new ground in giving us an understanding of what happens to gene expression with age,'' said Dr. Raj Sohal, a professor of biological sciences at Southern Methodist University. Although the study was with mice, he said it suggests that ''if you overeat, you are accelerating the aging process.''

  ''This study has analyzed more genes with regard to aging than all previous studies combined,'' said Prolla. He said 5 to 10% of the entire mouse genome was examined.

  In the Wisconsin laboratory study, the researchers fed one group of mice a regular diet while restricting by 24% the calories in the food given to another group. The diets all contained healthful levels of vitamins, minerals and proteins. Only the calories were reduced. This creates a condition of undernutrition, but not malnutrition, Weindruch said.

  After 30 months, muscles were taken from the animals and the activity of 6,347 genes was analyzed.

 ''We chose muscle for analysis because it is an important target for the effects of aging,'' said Weindruch. ''Muscle is lost routinely with old age and contributes to physical frailty.''

  The researchers found that more than 100 genes either increased or decreased their activity with age.  ''At the molecular level, normal aging looks like a state of chronic injury in muscle,'' said Prolla.  However, for mice fed the restricted diet, about 84% of the genetic alterations associated with aging were completely or partially suppressed.  ''At the molecular level,'' the study found, ''calorie-restricted mice appear to be biologically younger than animals receiving the control diet.''

 ''This clearly suggests that the reduction of calorie intake not only increases lifespan in mice, but seems to affect a broad spectrum of age-associated changes at the gene expression level,'' said Weindruch. He said these genetic changes clearly play a role in extending life in those animals.

 Many of the genes affected by aging are those that help the body rid itself of oxygen radicals, chemicals produced during the process of metabolizing calories in cells. Oxygen radicals are known to be damaging to DNA, the body's genetic material.

  Mice fed the full-calorie diet tended to lose the benefit of these oxygen radical control genes with age. The genes continued to work vigorously, however, in mice fed the calorie restricted genes.  Though the study evaluated muscles, Weindruch said that similar molecular effects may occur in the brain and in the heart, both of which tend to show the effects of the aging process.

Effect of Weight Reduction on Clinical Signs of Lameness in Dogs with Hip Osteoarthritis

Excerpts:

Weight reduction alone may result in a substantial improvement in clinical signs.

There is clear evidence that obesity is a significant risk factor for the development and progression of osteoarthritis. . .

Excess body weight will increase stress on weight bearing joints, and excessive cyclic stresses could contribute to degredation of articular cartilage and remodeling of subchondral bone.

Because obesity is also known to be a risk factor for osteoarthritis of the hand, alternative mechanisms such as metabolic alterations may also be important.

There is evidence that in humans with oseoarthrits,change in body fat percentage is more closely related to degree of symptomatic relief than change in body weight.

Some related reading:

R. Weindruch and R. L. Walford, The Retardation of Aging and Disease by Dietary Restriction (Thomas, SpringÞeld, IL, 1988).

 M. Shibanuma, J. Mashimo, T. Kuroki, K. Nose, J. Biol. Chem. 269, 26767 (1994); S. Wang, E. J. Moerman, R. A. Jones, R. Thweatt, S. Goldstein, Mech. Ageing Dev. 92, 121 (1996).

 K. B. Beckman and B. N. Ames, Physiol. Rev. 78, 547 (1998).

 W. C. Orr and R. S. Sohal, Science 263, 1128 (1994); T. L. Parkes et al., Nature Genet. 19, 171 (1998).

 M. H. Goyns et al., Mech. Ageing Dev. 101, 73 (1998).

 J. Jackman, I. Alamo Jr., A. J. Fornace Jr., Cancer Res. 54, 5656 (1994).

 O. Stachowiak, M. Dolder, T. Wallimann, C. Richter, J. Biol. Chem. 273, 16694 (1998).

 C. A. Peterson and J. D. Houle, J. Nutr. 127, 1007S (1997).

 Kealy RD, Lawler DF, Ballam JM, et al. Five year study on limited food consumption and development of osteoarthritis in coxofemoral joints of dogs. J Am Vet Med Assoc 1997;210:222-225

Lust G, Rendano VT, Summers BA. Canine hip dysplasia: concepts and diagnosis. J Am Vet Med Assoc 1985;187:638-640

Smith GK, Popovitch CA, Gregor TP, et al. Evaluation of risk factors for degenerative joint disease associated with hip dysplasia in dogs J Am Vet Med Assoc 1995;206:642-647

Plante I, Dupuis J, Beauregard G, et al. Long-term results of conservative treatment, excision arthoplasty and triple pelvic osteotomy for the treatment of hip dysplasia in the immature dog. Vet Comp Orthop Traumatol 1997; 130-l35 8. Mason E. Obesity in pet dogs. Vet Rec 1970;86:612-616

 Edney ATB, Smith PM. Study of obesity in dogs visiting veterinary practices in the United Kingdom. Vet Rec 1986,118:391-396

 Gentry SJ. Results of the clinical use of a standardized weightloss program in dogs and cats. J Am Anim Hosp Assoc 1993;29:369-375

 Cooper C, Inskip H, Croft P, et al. Individual risk factors for hip osteoarthritis: obesity, hip injury and physical activity. Am J Epidemiol 1998;147:516-522. 

Oliveria SA, Felson DT, Cirillo PA, et al. Body weight, body mass index and incident symptomatic osteoarthritis of the hand, hip and knee. Epidemiology 1999,10:161-166.

 Toda Y Toda T, Takemura 5, et al. Change in body fat, but not body weight or metabolic correlates of obesity, is related to symptomatic relief of obese patients with knee osteoarthritis after a weight control program. J Rheumatol 1998;25:2181-2186.

Butterwick RF, Markwell PJ. Changes in body composition of cats during weight reduction by controlled dietary energy restriction. Vet Rec 1996,138:354-357.

Felson DT Chaisson CE. Understanding the relationship between body weight and osteoarthritis. Ballieres Clin Rheumatol 1997;11:671-681.