two big guinea pigs outside eating
Some guinea pigs are just larger than others, but be alert to whether your guinea pig is packing on the ounces. FraukeFeind/

Guinea pigs must be among the most adorable animals on Earth, and once you gaze into the eyes of a guinea pig you will likely lose your heart. Their big guinea pig nose, delightful wheeking call, and unique walk endear them to almost everyone. As someone lucky enough to care for a pair or group of these precious beings, you might be tempted to spoil them.

Fair warning: Spoiling your guinea pigs is fine, but only to a degree and only in some areas. An extra, large habitat; plenty of toys; and lots of attention from you are wonderful ways to show your love to your guinea pigs. So is a balanced diet and some sensible treats, in moderation. This can be the tricky part. Food is an area where guinea pig fans might go a bit overboard. A fat guinea pig is not necessarily a happy guinea pig — and a fat guinea pig is certainly not a healthy guinea pig. But with a body shape similar to a rounded brick, how can you tell if a guinea pig is fat, and how do you prevent or treat guinea pig obesity?

How To Tell If Your Guinea Pig Is Fat

Determining whether or not a guinea pig is fat is not as simple as you might think. The normal body shape of a guinea pig can make this difficult. Also, some guinea pigs are just bigger than others. Guinea pig weights can vary from 900 to 1,200 grams for males and 700 to 900 grams for females, according to the book “Ferrets, Rabbits And Rodents Clinical Medicine And Surgery.”

Your best tool to use in determining your guinea pig’s weight status is a gram scale. Weigh your guinea pigs weekly to track their normal weight. Regular weigh-ins will help you spot any trends in weight gain or loss. A gram scale tracks smaller increments, which is why it’s more helpful to use for weighing small animals like guinea pigs.

Besides weigh-ins, observe your guinea pig. Does your furry buddy walk any differently? Does he seem more lethargic? Look at him from above to see if his sides are bulging out. If you notice anything that seems to hint at excess weight, don’t ignore it. The Guinea Pig-Size-O-Meter from the Pet Food Manufacturers’ Association in the United Kingdom offers more insight on what to look for to judge whether a guinea pig is overweight.

If you suspect your guinea pig is putting on weight, consult your veterinarian. A sudden gain or loss of weight could be a sign of a medical problem, including pregnancy or a tumor. Bloat involves distension of the abdomen that happens over hours; this is a medical emergency that needs immediate veterinary care. Once a medical concern is ruled out, get your veterinarian’s opinion about your guinea pig’s weight.

Preventing Guinea Pig Obesity

Hay And Guinea Pigs: Too much food and too little exercise are usually the cause of excess weight. One food that you can free-feed with confidence is hay. Guinea pigs rely on the high fiber of hay to wear down their constantly growing teeth and to keep their digestive tract moving. The nutrients in hay are important to guinea pig health. So don’t worry about feeding too much hay. As long as the hay is a grass hay and not alfalfa, give as much fresh hay daily as your little pals can eat. Alfalfa hay can only be fed to growing, sick or pregnant guinea pigs who need the extra nutrition and calories it contains.

Proper Guinea Pig Food: Besides hay, guinea pigs also need some other food. Some food, like vitamin C-fortified guinea pig pelleted food, are necessary for good health. Guinea pigs cannot make their own vitamin C, and over time get very sick without this vitamin. Other food, such as vegetables and some fruit, add variety and additional nutrients. Research the types of vegetables and fruit safe for guinea pigs to eat. For example, those that are high in calcium, oxalic acid, or sugar might need to be fed in limited quantities or not at all. And some foods that you consider healthy might actually be harmful to pets. Avocado and grapes are among these. The ASCPA’s Animal Poison Control Center maintains a list of people food to avoid feeding pets.

Guinea Pig Treats: Who doesn’t want to offer their furry buddy a treat now and then? And what guinea pig would ever refuse a treat? Treats are a wonderful bonding tool and also enrich your pal’s life, but be wise about the treats you offer. Offer treats in moderation, as guinea pigs who fill up on treats won’t eat their hay and regular diet. Vegetables and fruit in tiny portions can be used as treats, as can hay or pellets that are hand-fed. Anything hand-fed seems like a treat! Read the ingredients on any commercial treats and choose those that offer some nutrition and/or fiber.

No-No Food For Guinea Pigs: Candy, cookies, ice cream, cake, potato chips, doughnuts, cheese curls — the list of junk food could go on and on. And junk food for you is definitely junk food for guinea pigs. Any food with high fat, high sugar or high salt is a no-no for guinea pigs. Processed foods usually include one or more of these. Stick to simple, unprocessed food for your guinea pigs to maintain healthy weight.

Beyond Food: What a guinea pig eats is only half the story of weight gain. The other half is the amount of energy expended daily. If your guinea pig is an ‘X-pen potato,” find ways to help increase his or her exercise. Hide treats at opposite ends of the habitat, increase supervised out-of-cage time and play with your pal. Be creative and have fun. The more fun, the more likely your guinea pig will want to continue.

How Guinea Pigs Can Shed Weight

Consult your veterinarian to determine the best weight loss program for your guinea pig. Age, health status, and other factors affect what works best for each individual.

Exercise will likely play a role in weight loss. More free-roam time daily in a guinea pig-safe room under your supervision can help. Playing games with your pal and rotating toys that your guinea pigs can play with together while in their habitat are other ways to promote exercise.

Changes to a guinea pig’s diet must be done gradually. Cutting down on fruits or treats are likely starting points. A change in pelleted food brands or cutting back on pelleted food must be discussed with your veterinarian. Changing brands suddenly could trigger gastrointestinal upset or cause your guinea pig to stop eating pellets. Guinea pigs imprint on food early in life, which is why changes in diet must be done gradually. Cutting back on pellets might affect basic nutrition too much, as this is likely where your guinea pig is getting vitamin C. Again, this is where your veterinarian can guide you.

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