Body fat going up, muscle mass going down

WINSS Roundup Day 3



As human life expectancy has increased, so has the longevity of our pets. Animal nutritionists, therefore, need to respond by developing dietary products for senior dogs and cats. This is a relatively new field, however, with few long term studies to guide new research. Aging in humans is much better understood, so medical geriatric studies can help shed light on likely research trajectories for older animals.

One aspect of aging related to nutrition is muscle wasting. Whilst some loss of muscle is inevitable, if older people do not consume enough protein, the condition can worsen. Olav Rooyackers of the Karolinska Institute in Stockholm, Sweden opened day three of WINSS with an overview of muscle loss in aging, known medically as sarcopenia.

Muscle makes up around 40-50% of total body weight and is the body’s protein store. As we age both the quantity and quality of muscle mass declines. Despite its ubiquity, however, it can be hard to investigate this phenomenon. Scanning techniques that can assess muscle mass are improving, but there is so much disagreement on what constitutes sarcopenia, that studies put the proportion of the senior population affected at anywhere from 1 to 33%.

A protein rich diet and exercise can help delay the speed of muscle wastage, said Rooyackers, but neither can arrest it altogether.

Obesity is also a growing problem for the old, and for the population in general. Similarly in pets, talk of an “obesity epidemic” is now commonplace. According to the Association for Pet Obesity Prevention, roughly 54% of dogs and 58% of cats in the U.S. are overweight or obese.

But excess body fat is not the only issue that owners of portly pets have to face. Two studies presented at WINSS highlighted a clear link between obesity and undesirable behaviours in dogs.

Alex German of the University of Liverpool reported the results of an online survey conducted with the help of a UK TV channel. Overweight dogs were reported to be more likely to have undesirable behaviours such as eating faeces, guarding or stealing food and barking.

The survey respondents self-reported, so the exercise may have suffered from selection and reporting biases, and it was not possible to determine any causal links between behaviour and weight. It was noticeable, however, that owners of fatter dogs were more likely to refer to their animals as “like a baby” and indulged behaviours like sleeping on the bed. This may suggest that the type of relationship an owner has with his or her pet may be a predictive factor in weight gain.

John Flanagan of Royal Canin discussed the effectiveness of a weight loss diet for obese dogs. During a three month study, the dogs lost on average 6% of their bodyweight, but owners also reported improved behaviour. This indicates that weight loss interventions can benefit not just a dog’s health, but also its general attitude.

Continuing the strong Brazilian presence at WINSS, Iris Mayumi Kawauchi of Grandfood Indústria e Comércio LTDA, São Paulo, presented the results of a study on the effects of high and moderate protein diets on neutered dogs, concluding that a high protein diet was the one most likely to avoid weight gain.
Cat obesity did not escape the scrutiny of WINSS. WALTHAM’s Janet Alexander rounded up the morning’s presentations with an exploration of how the composition of macro nutrients such as carbohydrate and protein in cat diets affected weight gain. Whilst there seemed no categorical relationship that promoted healthy weight maintenance, portion control emerged as perhaps the most significant step owners can take in keeping cats on track.

The event wound up with early career researcher awards for the best poster and best presentation. Both winners came from the University of Missouri, Lauren Young for the presentation and Megan Sprinkle for the poster.

You can view the WALTHAM presentation here: