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Your Rat's Diet

Diet is one of the most important things to consider for your pet! You want to keep them healthy and the first place it begins is with their food! Diet plays major roles in overall health, weight, tumor prevention, and lifespan.

Sadly most packaged food sold by pet stores is nothing more than junk. It is filled with foods and nutritional content that is not even suited for that type of pet. It is shocking how many of them are filled with foods that your pet should not even have as part of their diet! 

Our pet's diet is one of the most argumentative subjects you can bring up among pet owners. It is right up there with the topics of religion and politics, as it can bring out the worst in people and cause normally sane people to lose their minds on what is right vs wrong. It seems everyone has an opinion and you may find that many claim their way is the only correct way. This means finding true and correct info a bit of an adventure.

WARNING: I am not a vet or animal nutritionist. I am not asking anyone to follow my advice blindly. Be smart, question things and do some research yourself. Secondly, I live in the US and so this is going to be very US based. I apologize. (for those in the UK I highly recommend visiting this forum)


Your rats diet & nutritional needs

Rats are opportunistic omnivores meaning they eat a varied diet of just about anything they find. Their diet mostly consists of grains, seeds, nuts, fruits, and veggies but also they will eat insects, eggs, fish, and smaller mammals! Rats can hunt even. 


From Wikipedia :

Martin Schein, founder of the Animal Behavior Society in 1964, studied the diet of brown rats and came to the conclusion that the most-liked foods of brown rats include scrambled eggs, macaroni and cheese, raw carrots, and cooked corn kernels. According to Schein, the least-liked foods were raw beets, peaches, and raw celery.[24]

Foraging behavior is often population-specific, and varies by environment and food source.[2] Brown rats living near a hatchery in West Virginia catch fingerling fish.[25] Some colonies along the banks of the Po River in Italy will dive for mollusks,[26][27] a practice demonstrating social learning among members of this species.[28] Rats on the island of Norderoog in the North Sea stalk and kill sparrows and ducks.[29]


Because of their opportunistic ways, many people believe that their pet rats can just live off scraps, their dinner left overs or just some mix of cereals and seeds and be healthy. This is most definitely not true.


There is a huge difference between surviving and thriving.  


I can probably survive on scraps & nothing but cheerios too but will I truly be healthy? Will I be getting all of my nutritional needs met? Will I be thriving? The same as us, rats have nutritional needs that need to be met.


A few notes...

  • Studies done on lab animals are not exactly equal to our pet rats in a pet home environment.

  • Different strains of rats can require different nutritional needs

  • Males, females, ages and activity levels all can play a role in their needs as well.

  • One thing people often do not think of is the source of the nutrition plays a role as well. 

This may mean that things are not exact numbers and may change as the rat does. More of an estimation or a guide.


This is a very detailed study on the nutritional needs of rats. 
Nutritional Requirements of the Laboratory Rat (1995)


This chart as well is interesting:
Estimated Nutrient Requirements for Maintenance, Growth, and Reproduction of Rats



What it breaks down to is how much fat, protein, carbs/fiber and vitamins/minerals a diet is made up of.


Fat- Around 5% is what you are going to be looking for.



Protein levels definitely change during a rats lifetime. The amount of protein a growing rat needs is much higher than that of an adult. And a doe lactating also has higher needs. (Many often want to up a pregnant rats protein, but you want to wait until after she has the babies and is nursing before doing so.)


The study linked above quotes that an adult rat's protein needs is 12%. For growth, they say 18-25%.

The image I have linked below (you will need to click to enlarge) is from the laboratory food maker Harlan Teklad (also knows as Native Earth), they say that for adult rats 14-16% and for growth 18%. They also say that too much protein can cause kidney damage in aging rats and mice. 



Ingredients matter as well as the quality of ingredients


One thing that really bothers me is when people compare two brands of food and go oh look they have the same ingredients so it is the same! This is not always the case. If a food is very inexpensive, you can guess that they are not sourcing ingredients from the best or highest quality sources. Pet food often has some low standards and shady iffy laws. I would definitely be concerned over the quality of ingredients.


Common rat food ingredients:

Corn- I am not a fan of corn in food. It is often just used as a very inexpensive filler. Do I really want my money to pay for filler or actual useful nutrition? Another thing I do not like about corn is that it has a fairly high glycemic index, which means it is high sugar and raises ones blood glucose fairly quickly. This concerns me being a major part (often the #1 ingredient) of the rat's diet. High sugar diets can lead to obesity and encourage tumor growth.
Dried corn seen in many mixes can be dangerous as it can contain mold. 


Alfalfa- In mixes this is just pure filler. Rats can not easily digest this grass and it is fairly pointless. Rats are not rabbits! In blocks, it is mostly used as a filler as well. 


Soy- People often fear soy and are afraid it will cause tumors. This is not true. There are actually really good studies done on breast cancer in Asian women whose diets were heavily soy based. These women had a lower risk of cancer coming back.




A carcinogen is a substance capable of causing cancer in living tissue. Many preservatives and dyes are known carcinogens. The FDA has said they should be fine for us humans to eat in limited amounts. I feel that even if one believes them to be safe in small amounts, feeding it as the main source of our rats daily diet, does not seem safe. More so when rats tend to be prone to tumors and that many of the studies done on these carcinogens were done on mice/rats and gave them tumors.


Red Dye 40 is a known carcinogen and used as a dye in some pet foods (some of Kaytee brands!) and even in some human foods.


BHA- a preservative used in some pet foods. It is a carcinogen- (as seen in some formulas of Mazuri)


BHT- another preservative.


Mixes VS Lab Block/Kibble


In my opinion lab block or kibble will always be better than mixes. They allow our rats to get solid complete nutrition as a whole. Whereas mixes could allow them to miss out on important parts of their diet because there is no way to make sure they eat each food item in a balanced way or even eat every type of item in the mix. 




  • They are able to pick & choose what they want & be picky about what they don't want. So they can eat all of one item, ignore others completely. This is more so when you have multiple rats. Rat A eats all of one item, and Rat B misses out. If half of their protein is from that source well their nutritional needs won't be met at all.

  • I feel mixes often lead to hoarding behavior. This leads to food often being completely wasted & thrown out (wasted money as well)

  • Rats are very small, tiny changes in the amount of one food or another will impact them greatly.

  • If you have multiple rats greedier more bossy rats may steal all the yummiest stuff meaning other rats will miss out on them entirely.And in turn, this can lead to fighting, bickering, bullying and stress in the cage.

  • So even if the diet mix is well balanced to meet their nutritional needs, it is very likely that the rats will never eat it in a balanced way and it completely defeats the purpose.

Store bought mixes often contain ingredients that are completely unsuitable or in the wrong unbalanced amounts- dried corn, alfalfa, too many nuts & seeds (high in fat), sugars, and also colors/dyes.

Lack of Variety?

The biggest complaint I hear about blocks is the lack of variety... first I think it is absurd as even with a mix they are still eating the same foods every day. How is that any different? How does eating the same 5 foods daily equal variety over eating the same single food? They are still eating the same thing every day.


Secondly, no matter what the base of their diet is you should always offer them fresh veggies, fruits, other whole foods, and treats. That is where the variety should come from!

Why is giving fresh foods ok but mixes are not? Because fresh foods are fed in small amounts in a controlled & scheduled manner. It means each rat is going to get roughly the same amount and you are aware of who is eating what.


Homemade mixes:

I often see many people wanting to make their own mixes and there are some guides around. Most of these guides are absurd and horrible. The makers have not taken any actual nutritional information into account when putting these together. They just said, "hey rats can and will eat this stuff so let's throw it all together!"


This does not make for any kind of healthy diet. Throwing together cereals, nuts, seeds, dried fruit and dog food is NOT a healthy well-balanced diet. Many cereals are loaded with sugars and some such as Total contains scary preservatives! Nuts & seeds are very high in fat and should be fed sparingly. Dried fruit is not the same as fruit, often contains added sugar and fruit in itself is too high in sugar to be fed often. 


There are some mixes out there that I think are not awful. I still do not like mixes for the many reasons listed above but there are people who have put in the effort and time to put together well thought out mixes. These often contain a variety of grains and very healthy ingredients and are not the budget-friendly option many are looking for when they want to do mixes.


Block/Kibble diet:

There are only 3 brands of food I recommend. These are the highest quality rat foods available.


  • Oxbow Essentials Adult Rat Food

    Oxbow is my food of choice and what I feed my rats. I feel it is the highest quality rat food on the market. It contains ideal protein and fat levels for adult rats. It does not contain corn or alfalfa.

    I like the smaller pieces and feel it helps toward preventing hoarding, none of my rats hoard food actually!

    Oxbow is the most expensive of the three. But IMO well worth the price for the quality you are getting. You can buy small bags at PetSmart or online but the smaller bags are quite expensive for the amount. It is much smarter to buy in bulk as the price difference is way lower. The bulk 20 lb bags will last most people a long time. It costs about $2/lb which 1 lb will generally last most rats 1 month. I do not feel $2 a month per rat as expensive.
     I purchase it through which is the best price I have found & they have free 2 day shipping on orders above $49 and normal shipping is just $5 ish

    I do not recommend feeding the young formula as it is not as high quality as the adult. Many rats also do not seem to prefer the taste of the younger formula either.


    Whole Brown Rice, Oat Groats, Wheat Bran, Wheat, Soybean Meal, Menhaden Fish Meal, Calcium Carbonate, Natural Flavor, Soybean Hulls, Brewer’s Dried Yeast, Flax Seed Meal, Monocalcium Phosphate, DL-Methionine, Canola Oil, Hydrolyzed Yeast, Wheat Germ Meal, Yucca Schidigera Extract, Salt, Inulin, Magnesium Oxide, Mixed Tocopherols (preservative), Choline Chloride, Sodium Bentonite, Vitamin E Supplement, Zinc Oxide, Manganous Oxide, L-Ascorbyl-2-Monophosphate (Vitamin C), Niacin, Copper Sulfate, Zinc Proteinate, Biotin, d-Calcium Pantothenate, Copper Proteinate, Manganese Proteinate, Riboflavin Supplement, Vitamin A Supplement, Pyridoxine Hydrochloride, Sodium Selenite, Thiamine Mononitrate, Menadione Sodium Bisulfite Complex (Vitamin K), Vitamin B12 Supplement, Vitamin D3 Supplement, Folic Acid, Calcium Iodate, Cobalt Carbonate, Rosemary Extract

    Guaranteed Analysis
    Crude Protein (min) 15.00%
    Crude Fat (min) 4.00%
    Crude Fiber (min) 2.00%
    Crude Fiber (max) 5.00%
    Moisture (max) 10.00%
    Calcium (min) 1.00%
    Calcium (max) 1.50%
    Phosphorous (min) 0.80%
    Vitamin A (minn) 8,000 IU/kg
    Vitamin D3 (min) 1,000 IU/kg
    Vitamin E (min) 125 IU/kg



  • Harlan Teklad/Native Earth
    You can find it sold on some sites, where they have opened the bags & portioned them out into smaller amounts that they then sell.

    I am not a huge fan of having to buy it already opened by someone. It gives me all kinds of worry on freshness, quality, and such. How do I really know what I am getting? I do not wish to speak ill of any site that does this. I probably have no cause for concern but it just does not sit well with me and is not something I would be comfortable in purchasing.

    The Native Earth version you can buy has 18% protein and is only sold in large bags.

    Harlan does contain corn. The blocks are fairly large in size and personally I found many wasted. My 100% non hoarding rats would hoard them, I think because they were larger and not able to eat them in a single sitting. They are often used in hoppers which makes their larger size better. There always seems to be a ton of dust in the bags and they can be super messy.

    This is a lab block. It is sold commercially as Native Earth. 

    Harlan comes in many different formulas and protein levels. The lower protein formulas can be more difficult to come by.

    Ingredients for the Native Earth 2018 Formula:
    Ground wheat, ground corn, wheat middlings, soybean meal, corn gluten meal, soybean oil, calcium carbonate, dried brewers yeast, dicalcium phosphate, iodized salt, L-lysine, DL-methionine, choline chloride, niacin, vitamin A acetate, biotin, pyridoxine hydrochloride,thiamine mononitrate, vitamin D3 supplement, folic acid, menadione sodium bisulfite complex (source of vitamin K activity), vitamin E supplement, vitamin B12 supplement, riboflavin, calcium pantothenate, ferrous sulfate, magnesium oxide, manganous oxide, zinc oxide, copper sulfate, calcium iodate, cobalt carbonate, chromium potassium sulfate.

    Crude Fiber (maximum)5.00%
    Crude Protein (minimum)18.90%
    Crude Fat (minimum)5.00%


  • Mazuri
    This brand of rodent food is made by Purina.

    It does contain both corn and alfalfa. They have different formulas with different protein levels. Some of the lower protein formulas do contain BHA though. Their common formula sold in pet stores has 23% protein, which I feel is a bit high for an adult.

    Ingredients of their formula in petstores:
    Dehulled Soybean Meal, Ground Corn, Wheat Middlings, Ground Wheat, Soybean Oil, Cane Molasses, Ground Oats, Calcium Carbonate, Dried Beet Pulp, Dehydrated Alfalfa Meal, Wheat Germ, Brewers Dried Yeast, Salt, Calcium Propionate, Dicalcium Phosphate, Pyridoxine Hydrochloride, Dl-Methionine, Choline Chloride, Dried Yucca Shidigera Extract, Menadione Sodium Bisulfite Complex (Source of Vitamin K), Vitamin D3 Supplement, Vitamin A Acetate, Folic Acid, Thiamine Mononitrate, D-Alpha Tocopheryl Acetate (Form of Vitamin E), Vitamin B12 Supplement, Niacin Supplement, Calcium Pantothenate, Riboflavin, Manganous Oxide, Zinc Oxide, Ferrous Carbonate, Copper Sulfate, Zinc Sulfate, Calcium Iodate, Cobalt Carbonate

    CRUDE PROTEIN23.0% min
    CRUDE FAT6.5% min
    CRUDE FIBER4.5% max
    MOISTURE12.0% max
    ASH8.0% max
    VITAMIN E50 IU/lb min



It is important to note that per my contract I require all adopters to feed one of these three brands of food listed above before I will sell to them. Diet is far too important to their overall health. I am open to discussing an alternative though.


Feeding Dog Foods:
Dog food can in some cases be ok for rats. I do not recommend dog food in most cases. High-quality dog foods are usually too high in protein and not suitable for a rats diet. Lower quality dog foods are often close in ingredients to many rat foods though but you do risk poor ingredients as well. 

I will supplement my nursing moms/growing babies with high quality dog food for extra protein, which moms and babies need. 

Doggy Bag-

This has become a popular food shared in many breeding and pet groups recently. It is dog food sold at tractor supply and is absurdly cheap. It is scary how cheap this food is. 100% it should never be fed to a dog, and I don't think it should be fed to any animal. 

I strongly feel this is poor, crappy, bad food. 

Many people say the ingredients and nutrients are similar to rat food, but the quality of ingredients matter too. In order to produce and sell a food that cheap, it is not going to have well sourced ingredients.


Feeding Cat Foods:
Do not ever feed cat foods. Cats and rats have very different nutritional needs. Cats are obligate carnivores. Any kindof of quality cat food will be far far too high in protein for rats.


Feeding Bird Foods:
No... while some seeds can be a nice treat, bird food is so not suitable for rats. Their base diet should definitely not be made up of a seed base.

Rabbit/Guinea Pig food:
No, this will kill your rats. Rabbits and guinea pigs eat a grass-based diet which does not contain nutrition for rats. Rats would become sick from malnutrition. 



Fresh Foods


Rats should be given fresh veggies, fruits, other foods often. I would suggest every other day or twice a week.

Always give more veggies then fruits. Fruits are great but higher in sugar. Do not give too much veggies/fruit or it can give them diarrhea. I like to mix up a small variety every week. You can give them a salad about the size of their head for each rat. 




Fresh foods I like to feed:
Spring Mix Greens
Carrots (not their favorite)

Pasta (cooked and dry)

Cooked Brown Rice
Hemp seeds
Eggs (scrambled or hard boiled- can have shell too but messy)
Chicken (rats can have bones even cooked, as there is no worry about splintering as they gnaw them)
etc.... (will update with more soon!)


Some of their favorite treats in moderation- cheerios multigrain, rice crispies (these are lovely for training as they are small and for teaching rats to be gentle taking food), Gerber baby snacks such as their yogurt drops or puffs.

I do not feed my rats snacks made for small animals or yoggies. These often have poor low quality ingredients and yet are more expensive then human alternatives, they are also full of sugars. Make your own yogurt drops by freezing yogurt!



Can rats have meat? Will feeding meat turn them into blood thirsty monsters?

I don’t know where this myth began, it is so silly if you think about it. Do you have a Dr Jekyll and Hyde situation from eating meat? no… Rats are opportunistic omnivores, they can eat meat, will eat meat and even will hunt/kill. I honestly think my rats favorite food is chicken! It will 100% not make them aggressive, mean, bloodthirsty or anything else like that. It will not cause them to bite or become cannibals either. It is food. I feed my rats meat in moderation (mostly moms/babies as I supplement extra protein for them), no one has become aggressive from it. And most brands of rat food include some type of animal protein.



Foods to avoid:

For the most part, rats can eat what we eat with a few exceptions. Remember the key is moderation!! 

Spicy foods

Peanut Butter - can be far too thick and pose a choking hazard

Blue Cheese can be toxic

Raw potatoes, sweet potatoes
Candy, gum, etc... They just do not need to eat this ever.

more info coming soon.....



How to feed:

IMO rats should have access to their block/kibble 24/7. I prefer a nice heavy bowl so it can not be spilled or knocked over. Let them free eat as they wish. If your rat is gaining weight first think about limiting or cutting treats.

They should also have access fresh water changed daily. I do suggest giving fresh water daily even if the bottle is not empty, it puts you in a good routine to check to make sure there is no issue with the bottle & that they do infact have water but also yay fresh water.
I prefer two or more water bottles just incase one is clogged or decides not to work for whatever reason. I also prefer multiple food dishes most of the time. Set on different levels/sides of the cage. This often prevents squabbles over food.

Fresh food should be given every other day or twice weekly. Giving it to them when they are up and active assures that it gets eaten in a timely manner. Remove leftover food before it rots. It is suggested that they get an amount of fresh equal to the size of their head.

Lab Block/Kibble should be about 80% of their diet with fresh food about 20%

*Some people prefer to scatter feed, which means hiding or scattering their kibble around the cage so they can find it. They say it is enriching. It is a personal preference. My rats do not stash food luckily, and I like a clean as possible cage so I prefer to use a dish. I think my rats get enrichment in playtime, toys and in treats- like making little balls with food hidden inside.

Let's discuss obesity....


Fat rats are not cute rats! They are unhealthy rats that are going to be prone to many health issues including but not limited to- increased risk of tumors, arthritis, heart issues, diabetes, hind leg degeneration, mobility and grooming issues, shortened lifespan.


Food doesn't equal love. Feeding your rat a bunch of junk food or overfeeding them is not a good way to bond or show love. It is cheap and easy but if you truly love them then you should care about their health as well.


But they have such short lives so let's spoil them... no. You are making their short life shorter and making their quality of life poor. I want my rats healthy and lively up until the end, not withered and in pain/suffering for half their life.

How to keep rats trim and healthy-

  • Feed a good healthy brand of food

  • Do not overfeed fresh foods or treats

  • Severely limit junk food or treats. Rats are very very tiny, a little goes a long way.

  • Keep their cage entertaining and exciting for mental stimulation- just like people bored rats can tend to overeat

  • Rats can also eat their feelings! Lone rats or stressed rats may over eat.

  • Wheels (12" +) and/or outside cage time may help.


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