Just add water

NEWCASTLE UPON TYNE, U.K. — A moisture-enhanced feline diet, coupled with increased activity, may inhibit the rate of weight gain in cats, according to research published in the June issue of the Journal of Animal Physiology and Animal Nutrition.

A string of studies conducted by Waltham Centre for Pet Nutrition in collaboration with the University of Aberdeen, showed cats that consumed a dry diet with approximately 50 percent water moisture gained weight at a slower pace and were more physically active than cats on a dry diet only with 10 percent moisture.

For the study, 27 domestic cats were put on a 20 percent calorie-limited diet. After restriction, cats were provided with the same dry diet without added water or with 40 percent water. Results showed that post-restriction weight regain was higher on the diet of high-energy density (with no hydration), in contrast to the diet of low-energy density (with hydration).

"The practical message is that the cats in this study gained body weight at a slower rate and were more active when fed dry food supplemented with water (total moisture content: 52 percent—natural content plus added water) compared with dry food without added water (total moisture content: 10 percent—natural content). Feeding a lower density high-moisture food to cats may help slow weight gain and increase activity level in cats," says Kerry Cameron, BSc, lead author of the study and research associate at the Institute for Ageing and Health, Newcastle University, U.K.

The study results mark the first time research demonstrated that a water-enhanced diet is related to a reduced rate of weight gain and a spike in physical activity in cats.

While conducting the study, Cameron says the goal was to find a way to manipulate pet food that would be simple for pet owners, hence, the addition of water.

"It's simple—owners can either include wet food in the cats' feeding regimen (ensuring that an appropriate amount of the dry food is reduced) or add tap water to a dry diet," Cameron says. "The additional benefit of feeding wet foods and dry foods (rather than adding water to dry) is that the crunchy texture of the dry food is maintained ensuring that any teeth cleaning benefits are not lost."

Surprising to researchers was the finding associated with physical activity. Cameron says that cats 'acted' like they did when they were on the restricted diet and exhibited more activity than cats on high-energy food.

When it comes to reducing pet obesity, Cameron says that body weight is all about balancing what goes in and out of the body.

"Like humans, cats probably don't get as much exercise as they should, and the incidence of feline obesity is rising. While it will depend how sociable a cat is, the more time you spend playing with it the more it increases activity and therefore burns calories. It's also good to encourage the cat to work for food by placing dry food in specially designed feeders that encourage activity in return for food," Cameron says.