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can hamsters overeat?

Can Hamsters Get Too Fat? (Healthy vs. Obese Weight Table)

Last Updated on: 24th September 2023, 05:39 pm

Hamsters are extremely active animals in the wild. So, they’re at risk of becoming overweight or obese in captivity, especially if they eat high-fat foods or lead a sedentary lifestyle.

Hamsters don’t overeat but are selective with the foods they eat. Many hamsters pick out the fatty seeds and nuts they enjoy from their food mixes, leaving any scientifically formulated pellets.

Also, hamsters get fat if they stop exercising or are less active. This can be due to many things, such as sickness or injury. Hamsters also slow down when they get old, gaining weight.

Can Hamsters Overeat?

It’s rare for hamsters to overeat as they only eat what they need to survive, stashing their food and nibbling on it during the day and night.

However, some hamsters are picky eaters, only eating the fatty, sugary items from their food mixes and leaving their pellets alone. Pellets don’t taste as nice, so many hamsters avoid them.

While this isn’t overeating, selective eating has the same effect, resulting in an unhealthy, unbalanced diet that leads to nutritional deficiencies, health problems, and weight gain.

Is My Hamster Overweight?

If you’ve noticed your hamster has suddenly gained weight or feels heavier than usual when you pick it up, you’ll be concerned about whether it’s getting too fat.

The best way to check your hamster’s size is to weigh it once a week using kitchen scales.

You may need to put your hamster in a bowl or cup to prevent it from moving too much. Make a note of your hamster’s weight each week to track any sudden or unexpected weight fluctuations.

All hamsters are different, and even male and female Syrian hamsters weigh different things.

This hamster weight chart shows the average healthy weights for each species:

Hamster SpeciesAverage Healthy Weight
Syrian120-200 grams
Roborovski25-30 grams
Chinese30-45 grams
Winter White30-45 grams
Campbell’s30-45 grams

Pet store hamsters tend to be smaller and lighter than ethically bred hamsters. Similarly, as touched upon, female Syrians are larger and heavier than males.

Don’t be alarmed if your female hamster is at the higher end of the weight scale. Females are larger to survive procreation, so a heavier weight is normal.

How To Tell If Your Hamster Is Obese

While weighing your hamster is the best way to keep track of its weight, there are several ways to tell whether a hamster is obese by the way it looks, feels, and behaves. Overweight hamsters:

  • Feel heavier than usual.
  • Have a noticeable layer of fat around the abdomen.
  • Display visible fat rolls on either side when they stand up.
  • Find it difficult to move around the cage.
  • Become lethargic and inactive, sleeping for longer.

Hamsters are small, so weight gain is sudden and unexpected.

What Does a Fat Hamster Look Like?

Fat hamsters will look round, even when standing.

Look at your hamster from above to get the best view of how round it’s become. You may also want to take frequent pictures to give yourself a reference to a healthy weight.

causes of obesity in hamsters

Why Is My Hamster Fat?

It’s normal for a hamster’s weight to fluctuate. However, excessive weight gain is unhealthy. There are several causes of obesity in hamsters, such as:


Owners commonly overfeed their hamsters, as they’re concerned they’ll run out of food.

Hamsters store their food in their cheek pouches, moving it somewhere safe for later. Small Animal Dermatology explains how the cheek pouches extend far down the body and expand like a balloon.

Hamsters can also pack them to capacity due to special retractor muscles. Because hamsters can fill their pouches with so much food, they can appear to have eaten it all overnight.

Syrian hamsters need approximately 1-2 teaspoons of food every 24 hours, while smaller dwarf species need around 1-2 teaspoons over 48 hours.

They can also have small amounts of fresh fruits and vegetables every day.

Unhealthy Diet

A study by Experimental Animals found that a diet high in simple carbs and lipids contributes to obesity. However, inflammation contributed to weight gain.

That’s why hamsters must receive a balanced diet, including formulated pellets.

Lack of Exercise

Highly active animals must keep their bodies healthy by running on an exercise wheel, foraging for food, and playing with toys. They also benefit from regular out-of-cage time.

Once the hamster stops exercising or reduces its movement, it’ll gain weight. This is most likely to happen in the winter when it gets cold and sleeps longer. Hamsters stop exercising due to the following:

  • Sickness.
  • Injuries.
  • Stress.
  • Old age.

A lack of exercise causes heart disease, diabetes, and stress, worsening pre-existing health conditions.

What Foods Make Hamsters Fat?

Besides scientifically formulated pellets, hamsters must eat all other foods in moderation to prevent selective eating and weight gain. However, there are food items to be mindful of more than most.

The following foods are most likely to make your hamster fat:

Nuts and Seeds

Hamsters enjoy the taste of seeds and nuts. They also like biting and cracking open their hard shells for mental stimulation. This action has the added benefit of keeping their ever-growing teeth filed down.

Some of the worst culprits include the following:

  • Cashew nuts.
  • Hazelnuts.
  • Peanuts.
  • Walnuts.
  • Almonds.
  • Pecans.
  • Sunflower seeds.
  • Pumpkin seeds.
  • Flax.
  • Sesame seeds.

Restrict feeding your hamster nuts and seeds to once or twice a week.

Lean Protein

Hamsters are omnivores. As well as plant-based foods, they require approximately 16% protein in their diets to stay healthy. Good protein sources include:

  • Hard-boiled eggs.
  • Plain cooked chicken.
  • Mealworms and crickets.

However, too many high-protein foods will cause your hamster to gain weight. As hamsters, especially the dwarf species, are so small, they only need a modest amount of protein.

Sugary Fruits

Fresh fruits and vegetables give hamsters the nutrients they don’t get from their usual food sources. They also provide additional hydration, preventing dehydration.

While fruits and vegetables are okay for hamsters, sugary fruits, like bananas, will cause the hamster to gain weight. They’re also responsible for diarrhea, which is dangerous for hamsters.

You don’t need to cut out these foods completely. Instead, focus on feeding your hamster plenty of greens, such as spinach, cucumber, kale, and broccoli.

Fatty Meats

Even though hamsters can eat a small selection of meat, fish, and seafood, you mustn’t provide your hamster with fatty meats.

Any meat you feed your pet hamster should be devoid of oils, seasonings, and added ingredients to prevent your hamster from consuming unnecessary fat and calories.

For example, fried chicken or processed ham is packed with saturated fat.


Some owners prefer to feed their hamsters muesli over a pellet or seed mix. Unfortunately, muesli contains filler foods that are too high in fat and sugar.

Hamsters are prone to picking out the bits they like from the mix.

can hamsters die from being overweight?

What Does It Mean When Your Hamster Gets Fat?

If your hamster gets too fat, it means one of the following:

  • Excessive food consumption.
  • Too many high-fat, sugary foods are being eaten.
  • More exercise is necessary.

Ensure your hamster can access a large exercise wheel and toys to play with and chew.

Can Hamsters Die from Being Overweight?

Obesity is a significant problem for hamsters. Weight gain kills hamsters for these reasons:


Overweight hamsters are more at risk of developing type 2 diabetes than healthy hamsters. It more commonly occurs in dwarf species, although Syrians can develop it. Signs of diabetes include:

  • Frequent urination.
  • Dehydration.
  • Increased thirst.
  • Changes in appetite.
  • Thick, yellow nails.
  • Lethargy.

Type 2 diabetes can be controlled with vet-prescribed medication and a healthy diet.

Heart Problems

Too much fat strains the heart, leaving a hamster vulnerable to problems. Many overweight hamsters experience heart failure, causing them to die without warning.

Liver Disease  

A study by Dove Press discovered that hamsters exposed to a high-fat, high-cholesterol diet are more likely to develop fatty liver disease and diabetes.