Family running in field with family dog supporting their health through diet

Dr. Gary Richter Discusses Whole-Food Nutrition of Our Pets

Veterinarian Dr. Gary Richter explains why standard dry and canned food is so harmful for your pet. He details the best foods to support your pets’ overall health.

Scientifically reviewed by Dr. Gary Gonzalez, MD, in August 2023. Written by: Gary Richter, DVM.

Eating a whole-food diet is critical for a human’s optimal health and longevity, but what you feed your pets is important for their health and well-being as well.

Dogs get cancer at approximately the same rate as humans. They also suffer from heart disease, arthritis, allergies, gastrointestinal problems, and many other health issues that are similar to those faced by humans.

Their diet could be the reason.

As veterinarian Gary Richter explains here, standard dry and canned foods are highly processed foods that produce inflammation and harmful advanced-glycation end products in pets the same way that processed food does in humans.

Pet owners who switch to more natural diets for their animals report that the pets experience benefits like more energy, a healthier hair coat, better digestion, and dramatic improvements in gastrointestinal issues and allergies.

In this eye-opening interview with Life Extension®, Dr. Richter explains why standard kibble and canned food are so harmful for your pet. He also details the best foods to feed your pets to support their overall health.

—Laurie Mathena

LE: We know that eating a healthy diet is critical for humans, but how critical is it for our pets to eat an optimal diet as well?

Dr. Richter: Readers of Life Extension® are no strangers to the concept of optimal nutrition being a cornerstone of good health and longevity.

Even to the uninitiated, it is common knowledge that fresh, whole foods are better for your health than highly processed foods.

Despite it being self-evident when it comes to our own health and longevity, it is likely many have not considered the concept of fresh, whole food for our pets.

Every animal on earth evolved eating a fresh, whole-food diet, and that is how all biological systems evolved to function optimally.

After all, there were no bags or cans of food millions of years ago when evolution was hard at work developing what has become today’s animalkingdom.

All species function at their best when they consume the nutrients on which their bodies are designed to thrive.

While an optimal diet clearly varies from one species to the next (herbivores, carnivores, omnivores, etc.), the common through line is that fresh, whole foods are best for all animals.

LE: Does this mean that standard canned and dry kibble isn’t good for our pets?

Dr. Richter: With the understanding that an optimal diet for any animal is going to be made from fresh, whole foods, let’s consider most pet food today.

Walk into any large pet store and you are faced with shelves full of kibble and canned food.

The companies that make these foods would have you believe these are “optimal” nutrition for your dog or cat.

They put pictures of fresh food on the labels and aggressively advertise on TV, in print, and on the Internet to let you know the food in that bag or can will keep your pet healthy and happy for a lifetime.

On closer examination however, the veneers of these foods peel back surprisingly easily.

LE: How can you distinguish a beneficial product from a harmful one?

Dr. Richter:Start by reading the ingredient list. Many middle-to-lower tier foods use meat by-products and meat meal as protein sources.

While some ingredients that go into by-products or meal could be healthy for your pet, we have no way of knowing what is actually in there. Some of the possibilities include hooves, horn, beaks, feathers, and wool.

Similarly, many pet food companies use carbohydrates like grains, legumes, etc., as a cheaper source of calories than meat and as a filler and binder for dry foods.

Dogs, and especially cats, are not evolutionarily adapted to high-carbohydrate diets.

LE: Is this a problem with premium brands as well?

Dr. Richter: Even the “premium” brands of pet foods are highly problematic for dogs and cats.

Read the ingredients of top-tier dry and canned foods and you will find ingredients that look good. In fact, they are good ingredients—or at least they were.

When you open that bag or can of food for your pet, how much does what you see resemble the high-quality fresh ingredients you read listed on the label?

LE: How have such inferior products become the standard diet for our pets?

Dr. Richter: A good thing to remember is dry and canned pet food exists for only one reason—our convenience.

The ability to have food for our pets that requires no refrigeration and is shelf stable for years is undeniably attractive.

The trouble is, preventing fresh food from spoiling without refrigeration often requires things to be done to the food that aren’t necessarily in the best interest of our pets.

The shelf stability we see in most processed pet foods is achieved through the use of very high heat and pressure during processing. This kills pathogens that could lead to spoilage but creates a host of concerns that could prove harmful to our pets.

LE: Why is something like high heat problematic?

Dr. Richter: High heat and pressure frequently lead to loss of vital nutrients.

Anyone who has experienced overcooked meat or vegetables will instantly understand what this does to food.

You don’t need to be a clinical nutritionist to recognize that overcooked food is not as nutritious as fresh or lightly cooked food.

As problematic as what is missing from highly processed pet foods is what is created during the high-heat and high-pressure cooking process.

Advanced glycation end products (AGEs) and Maillard reaction products (MRPs) are both produced as a result of proteins and carbohydrates being exposed to heat and pressure.

These chemical compounds are well known to promote inflammation and have been linked to cancer.

AGEs and MRPs are one of the main reasons why it is so important for people to eat fresh whole foods. It is also why fried foods and charred meats are frowned upon by nutritionists and longevity experts.

These foods cause inflammation in our bodies, and inflammation is the root cause of many chronic diseases experienced by humans and animals alike.

Perhaps one of the most disturbing aspects of processed pet foods is the amount of these toxins our pets are consuming.

When researchers evaluated the presence of MRPs in dogs and cats that consumed kibble or canned diets, it was found that dogs and cats consume 122 and 38 times more MRPs per day, respectively, than the average adult human!

LE: Are there any guidelines or regulations for what can and cannot be included in commercial pet food?

Dr. Richter: While there are nutrition standards set forth by the American Association of Feed Control Officials (AAFCO), these are minimum standards that ensure animals will not suffer from illness due to nutrient deficiencies.

These standards are largely concerned with macronutrients like protein and fat, and vitamins like vitamin A, B, C, D, etc.

There is no accounting for where the nutrients come from, as well as many micronutrients.

AAFCO standards provide an excellent minimum standard for pet food, but there is a lot of daylight between “minimum” and “optimal” nutrition.

If you want your car to function perfectly, you need to put in the type of gas and oil with which it was designed to function optimally.

The same is true for any biological specimen. It can function with minimum standards, but if you want it to work as well as it can for as long as it can, we need to do much better.

LE: If kibble and canned diets for our pets are so problematic, are there alternatives?

Dr. Richter: Fortunately, yes. And they don’t all require you to home cook food for your dog or cat.

There are many fresh, whole-food diets for dogs and cats available in pet stores and on the Internet.

They come in several formats, including fresh-frozen cooked, fresh-frozen raw, freeze-dried raw, and dehydrated foods.

LE: What does an ideal diet look like for our pets?

Dr. Richter: In a perfect world our pets would all be eating either raw or lightly cooked diets. These diets are about as close to our pet’s evolutionary diet as we can get.

These diets come in a variety of proteins and can be either purchased or made at home.

Clearly, buying food that merely needs to be thawed and fed is more convenient, but it also is more costly.

Making fresh food at home is an excellent, and more cost-effective option for people who don’t mind spending a little time in the kitchen.

The goal with making food at home is to make as much food as you have space for in the freezer. Some people with multiple pets or large dogs purchase a chest freezer for the garage and store the pre-portioned food in there and thaw it as necessary.

The one critical thing to remember when making pet food at home is you must use a recipe balanced by a nutritionist. You cannot create a balanced diet by putting meat and vegetables in a bowl.

Books are available with balanced recipes and nutritionists are also available for consultations.

LE: You mentioned freeze-dried foods. Are these a good option for someone who doesn’t want to make homemade food?

Dr. Richter: Freeze-dried and dehydrated foods are an excellent option for many pet owners.

Freeze-drying is a process by which moisture is removed from cold, fresh food under a vacuum, while dehydrating uses heat to remove the moisture.

Either way, the result is food that is shelf stable, weighs very little, and is much better for pets than more highly processed foods.

The amount of processing with freeze-drying and dehydrating does not lead to the degree of nutrient loss or the creation of AGEs and MREs we see in kibble and canned diets.

Feeding these foods is about as easy as it gets. Just add water.

LE: What about cost?

Dr. Richter: Freeze-dried and dehydrated foods are often a little less costly than frozen foods, and they have the added benefit of being shelf stable.

This is a great option for people lacking extra freezer space.

It’s also great if you tend to travel with your pet. You won’t need to worry about traveling with frozen food if you are using a freeze-dried or dehydrated option.

LE: What are the benefits of feeding our pets this type of food?

Dr. Richter: In my experience as a veterinarian, most people who convert their pet to a fresh, whole-food diet report having an overall healthier pet, with more energy, a healthier haircoat, and better digestion.

I have seen countless pets with chronic gastrointestinal issues and allergies dramatically improve on nothing more than converting to a fresh, whole-food diet.

LE: How difficult is it to switch your pet to a whole-food diet?

Dr. Richter: Switching to a fresh diet is easy.

The goal is to make a gradual transition. This allows your pet’s digestive tract to make the adjustment from processed foods to fresh foods.

In addition, for picky eaters (I’m looking at you, cat owners), a very slow transition is often the key to getting pets to accept a new food.

Begin by adding a very small amount of new food to their old food. Each day, add a little more new food and take away a little more old food.

Depending on whether your pet has a sensitive GI tract or if it’s a picky eater, take anywhere from one to three weeks in the transition.

There is no hurry. Take longer if you need to.

LE: Once you find a food that works for your pet, should you stick with that one food exclusively?

Dr. Richter: When it comes to fresh-food diets, there is no absolute right or wrong, although there are some good guidelines to follow.

Variety is a good thing to provide a spectrum of nutrients and to prevent dietary sensitivities caused by prolonged exposure to one protein over a very long period of time.

Some pets can easily switch from one protein to another with no problem, while others are a little more sensitive.

For our pet friends with sensitive tummies, consider a gradual transition to a new protein every three to four months.

Feeding more than one format of food is fine, as long as your pet does OK with it.

In other words, if you want to feed some fresh and some freeze-dried, that is fine. Some people do this so their pet is accustomed to freeze-dried for when they go out of town with it.

Additionally, if it is financially challenging to feed your pet exclusively a fresh, whole-food diet, feed them as much as you can, and for the rest use high-quality canned food or kibble.

Just as with us humans, eating some fresh food and some processed food is better than eating exclusively processed foods.

LE: What about table scraps? Should you feed your pet food from your plate?

Dr. Richter: That depends on what you are eating.

Pets don’t do well with spicy or highly seasoned foods so those should be avoided. Also, avoid foods high in fat as they can cause GI upset, and never give them foods containing onions, grapes, raisins, or macadamia nuts, as these can be toxic.

With that said, if you want to put a little something from your plate in your dog or cat’s bowl, go ahead—sharing is caring.

Just make sure it’s only a little because we want them to be mostly eating a fully balanced, fresh whole-food diet to meet all their nutritional needs.

LE: How difficult is it for a pet owner to make the switch?

Dr. Richter: Feeding your pet a fresh, whole-food diet is easier than it has ever been.

Whether you choose fresh frozen, homemade, freeze-dried, or dehydrated foods, you are taking the single biggest step anyone can take to ensure a long and healthy life for an animal.

The greatest thing about pet nutrition is that we are completely in control of what they eat.

It is much easier to feed a pet an optimal fresh, whole-food diet than it is for us humans. Their willpower doesn’t come into play.

It’s no secret how critical optimal nutrition is for human health and longevity. It is all the same for our pets.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

Dr. Gary Richter specializes in holistic veterinary care. From 2002-2021, he was the owner and medical director of Montclair Veterinary Hospital in Oakland, California. He launched Holistic Veterinary Care in 2009, also in Oakland. His animal hospitals have received more than 30 local and national awards, including Best Veterinary Hospital, Best Veterinarian, and Best Alternative Medicine Provider. He was named one of the top 10 veterinarians in the US in 2012, America’s Favorite Veterinarian in 2015, and he received the Holistic Practitioner of the Year Award in 2019.

Dr. Richter also wrote an Amazon Best-Selling book, The Ultimate Pet Health Guide. For more information, visit