Hill’s Prescription Diet i/d Low Fat Review – Is It Effective?

June 29th, 2020

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A yellow Lab smacking her lips on a hike after eating a delicious treat!

Table of Contents

Disclaimer: This post contains affiliate links for various pet products. This means that, at no additional cost to you, I’ll earn a commission if you click through and make a purchase.

Due to a diagnosed gastrointestinal problem, your vet may recommend a special prescription diet for your dog.

Among the most common and popular choices is Hill’s Prescription Diet, i/d Low Fat.

Is it effective? And is this food safe and healthy? Is it worth the markup price?

After nearly two years of including Hill’s Prescription Diet i/d Low Fat in Yuna’s meals, we’ll do a deep dive review into this food. Note that for canines, both dry food and wet canned food options exist. We’ll focus only on the dry kibble version in this review.

Who Is Hill’s Prescription Diet i/d Low Fat For?

As Hill’s Prescription diet is a prescription food, you can’t just walk into a pet store and grab a bag off the shelf.

A written prescription from the vet is required. This applies to pet stores and reputable online sellers.

That being said, if your vet does diagnose your dog with a particular issue in the gastrointestinal (GI) tract, Hill’s Prescription Diet i/d Low Fat may be the perfect option for them.

“Gastrointestinal issue” here is relatively broad. Any number of issues, ranging from mild ones like diarrhea or constipation, to more serious ones like pancreatitis or chronic gastritis.

Hill’s Prescription Diet i/d Low Fat has often helped dogs with the following conditions:

  • Generally sensitive tummy/consistently soft stools
  • Vomiting
  • Diarrhea
  • Constipation
  • Pancreatitis
  • Gastritis
  • Colitis
  • Inflammatory bowel disease
  • Intestinal lymphangiectasia (Protein losing enteropathy)

Hill’s i/d Low Fat has also been known to help with weight management in dogs, although we only recommend this product to dogs suffering a specific GI issue.

In short, if your pup is facing any type of digestive issue, Hill’s may be right for you.

i/d Meaning

This kibble is specially formulated to help with the specific doggy demographic we mentioned above.

The “i/d” acronym by Hill’s stands for intestinal diet. Food labeled as i/d is characterized as being highly digestible, suitable for dogs with “sensitive tummies.”

Mm... I got a sensitive tummy. Can anyone relate??

Is Hill’s i/d Low Fat Effective In Calming The Digestive Tract?

The official listing for Hill’s Prescription Diet i/d Low Fat makes five claims to justify its i/d designation:

  • Highly digestive & low in fat
  • Enriched with prebiotic fiber & ginger
  • High levels of omega-3 fatty acids
  • Controlled minerals
  • Clinically proven antioxidants

Do these claims hold water? We’ll put each one to the test.

Highly Digestive & Low In Fat

In taking a look at the major ingredients of this kibble, many of the ingredients do not feature a traditional animal-based protein in many other commercial foods.

Instead, a lot of the protein comes from Brewer’s rice, corn starch, corn gluten meal, whole grain wheat, and chicken by-product meal.

Some of the ingredients here are controversial. This may set off alarm bells for a lot of pet owners. We’ll discuss whether this is a bad thing later in this article.

However, these ingredients do support the claim that the food is highly digestive. Brewer’s rice and corn are easier on a dog’s stomach even though they’re considered lower-quality dog food ingredients.

Also, according to Dog Food Advisor’s dry matter nutrient content, the food is 15% fat, which is lower than most commercial kibbles.

Enriched With Prebiotic Fiber & Ginger

Prebiotics are a type of fiber that feed the good bacteria in the gut. They improve digestibility of food.

Certain ingredients in Hill’s i/d Low Fat contain prebiotic fiber, including flaxseed, dried beet pulp and soybean oil.

Ginger is also on the ingredient list. It has soothing effects on the digestive system particularly in preventing nausea and vomiting as well as bloat in dogs.

High Levels of Omega-3 Fatty Acids

Omega-3 fatty acids are known to have many benefits in dogs, including reducing inflammation, supporting the immune system, and boosting heart and kidney health. Digestive benefits are not usually a directly touted benefit, but they’re important in a balanced diet.

The guaranteed analysis of the food claims a minimum of 0.6% Omega-3 fatty acids. This is generally higher than other dog foods (i.e. Taste of the Wild High Prairie: 0.3% minimum).

Controlled Minerals

This one is tough to gauge. Pretty much all dog foods will feature a list of vitamin and mineral supplements that take up the bottom half of the ingredient list.

Minerals that are explicitly listed on Hill’s i/d Low Fat include:

  • Ferrous Sulfate (ensures your dog gets enough iron, an important nutrient)
  • Zinc Oxide (zinc is another important nutrient, although Zinc Oxide is often considered a lower quality source, compared to Zinc Chelate).
  • Copper Sulfate (Copper supplement; okay in low quantities)
  • Manganous Oxide (Source of manganese, essential for bone growth and thyroid hormone production)
  • Calcium Iodate (Iodine supplement)
  • Sodium Selenite (Selenium supplement)

All of these are considered essential minerals, and okay in very small quantities. Too much of any one can be toxic to your dog.

As these minerals appear very late on the Hill’s Prescription Diet i/d Low Fat ingredient list, this should be fine for your dog.

Note also that according to Dog Food Advisor, the minerals do not appear to be chelated, which means they may be more difficult to absorb.

Clinically Proven Antioxidants

Antioxidants help support the immune system and neutralize “free radicals, oxygen-containing molecules that can damage cells, membranes, and even DNA.

Hill’s Prescription Diet i/d Low Fat contains a combination antioxidant, with vitamins E and C, selenium, and beta-carotene, all of which help neutralize free radicals.

AAFCO Approved - Adult Maintenance

In addition to the five promoted benefits, animal feeding tests using AAFCO (Association of American Feed Control Officials) procedures substantiate that Hill’s Prescription Diet i/d Low Fat Canine provides complete and balanced nutrition for maintenance of adult dogs.

AAFCO nutrient profiles come in five different flavors. Hill’s i/d Low Fat has the [M] symbol, meaning it’s designed for dogs in adulthood.

Personal Experiences With Yuna

For Yuna, Hill’s Prescription Diet i/d Low Fat worked like a charm. A consistent diet involving Hill’s was largely responsible for soothing pancreatitis symptoms.

A dog looking goofy with her tongue out sideways.

After a few months of strict feeding of only Hill’s i/d Low Fat, Yuna was cleared of her pancreatitis diagnosis and is now allowed to eat regular foods again.

In general, her stools have also thickened (they were consistently soft previously) and she rarely if ever vomits.

In order to prevent symptoms from resurfacing, we still mix in half of Hill’s i/d Low Fat along with another regular dog food.

Is Hill’s Prescription Diet i/d Low Fat Safe And Healthy For Your Dog?

Earlier on in this review, we noted that the ingredient list looks suspect at first.

Normally, we want an animal-based protein to make up the first couple of ingredients. Looking at the list for Hill’s Prescription Diet i/d Low Fat, the top 5 ingredients are:

  • Brewers Rice
  • Corn Starch
  • Corn Gluten Meal
  • Whole Grain Wheat
  • Chicken By-Product Meal

Some of these ingredients are controversial. Let’s do a quick look into each one and analyze why it’s there, and whether it could be harmful for your dog.

Brewers Rice

Brewers rice is small fragments of rice kernels that have been separated from larger kernels of milled rice.

It often gets a bad rap because it’s considered the “leftovers” from white rice. Look up any picture of Brewers rice and it also doesn’t look aesthetically pleasing.

It’s true that Brewers rice is a cheaper alternative to, say, white rice. Grains don’t contain much nutritional value for dogs, but Brewers rice is an ingredient that contains very easily digestible carbohydrates with fiber.

That’s precisely what we’re after with a digestive care food. Obviously, a food with Brewers rice as the top ingredient would not pass as a high-quality regular dog food.

But this kibble is therapeutic, so we shouldn’t judge it based on traditional standards.

Note On Portioning

Know that since a high carb ingredient takes the top ingredient spot, overfeeding can make your pet gain weight rapidly.

From personal experience, we believe that the recommended feeding guide printed on the bag is a little too much.

Yuna is a 60 pound lab. The label recommends 3 ¼ cups per day for her weight class, but I feed her only about 2 ½ cups on a normal day (she gets about 60 minutes of exercise). This keeps her weight stable.

We recommend starting with the feeding guide, and tinkering that based on how your dog’s weight responds.

A yellow Lab smiling candidly in a pink Winnie The Pooh bandana.

Corn Starch & Corn Gluten Meal

Corn, in general, is another controversial ingredient. Corn starch and corn gluten meal round out the podium of Hill’s ingredient list–is this problematic?

Again, most people would prefer that a protein take up the first, or first few, ingredients. However, as this article notes, most consumers should favor a dog food because meat is the first ingredient, not just protein.

This is because meat doesn’t just contain protein, but fat as well.

Most dogs with digestive issues require a diet with lower fat levels.

The experts at Hill’s know this, and deliberately picked corn as a main energy source because it’s fat free.

Whole Grain Wheat

To make a controversial ingredient list even more controversial, Hill’s has whole grain wheat as the fourth ingredient.

Since we began domesticating dogs, they’ve gradually adapted to accommodate grain in their diets. This hasn’t stopped people from denouncing grains in a diet.

But whole grains can provide a myriad of benefits as well. For example, fiber from whole grains helps regulate the digestive system.

Grains are also not without protein, but come in more reasonable quantities suitable for dogs with GI problems.

If your dog has a grain allergy, do consult with your vet before choosing this food. Grains are cited as one of the more common allergies in dogs.

Chicken By-Product Meal

Chicken By-product meal is the parts of the chicken other than the meat, and then cooked. It’s considered another evil by many, who say it’s lower-quality than actual animal meat.

By-products are parts of the animal that many people in the US consider inedible. The truth is, many parts of a chicken, such as chicken feet, liver, and gizzards are commonly consumed in other areas of the world.

These parts often provide even more nutrients than meat on a per-weight basis. So the notion that they are somehow inferior in quality and nutrition is simply not true.

In Hill’s i/d Low Fat, this ingredient rounds out the top 5 by adding some more protein for a balanced diet.

Final Word On Ingredients

If we were to judge this kibble based on traditional standards, then yes, you can find higher quality sources of protein and fat from other commercial diets.

However, the ingredients here were all selected very carefully for the target canine audience of this food.

For a dog with gastrointestinal issues and who require a low fat formula, Hill’s Prescription Diet i/d Low Fat delivers without compromising on nutrition.


Now, onto price. Compared to other commercial kibbles, Hill’s Prescription Diet i/d Low Fat is not cheap.

The food comes in three bag sizes: 8.5 lb, 17.6 lb, and 27.5 lb. The following chart compares the price as well as price per cup for each bag:

Bag WeightRetail PriceApprox. CupsPrice Per Cup
8.5 lbs $38.99 34 $1.15
17.6 lbs. $65.99 70.5 $0.94
27.5 lbs. $89.99 110 $0.82

We normally recommend that you buy the size suitable for your dog, because after opening a bag of kibble, it’s often hard to reseal.

However, Hill’s Prescription Diet i/d Low Fat comes with a resealable opening to help the food stay fresh. Since it’s also more expensive than your typical commercial kibble, we recommend considering going one size up.

Let’s consider the price per cup across other commercial kibbles, as well as Purina Proplan Veterinary Diet (another commonly prescribed diet for digestive care):

Brand & SizeTypeRetail PricePrice Per Cup
Hill’s Prescription Diet, i/d Low Fat (27.5 lbs) Vet $89.99 $0.82
Purina Pro Plan Veterinary Diets EN Gastroenteric (32 lbs) Vet $97.99 $0.77
Taste of the Wild, High Prairie (28 lbs) Commercial $48.99 $0.44
Orijen Dry Dog Food (25 lbs) Commercial $90.99 $0.91

(Prices here current as of time of initial post, June 2020. For most up to date prices, check listings on Amazon):

We purposely included both a cheaper and more expensive commercial option in this comparison. Note that depending on what commercial brand you pick, it could potentially outprice Hill’s.

However, in general, most veterinary prescription diets are going to be more expensive than your regular store shelf kibble.

In some cases, as you can see, Hill’s can run almost twice as expensive as the popular Taste of the Wild.

Is It Worth It?

The final question, then, is if Hill’s i/d Low Fat is worth it.

If you looked at the ingredient list, you might conclude that due to the relative lower-quality ingredients used, the price of this product isn’t justified.

And it may seem weird to you that while these cheaper ingredients are being used, that lower production cost hasn’t translated into the price label.

However, the product offers a benefit that most commercial diets simply cannot offer.

Most commercial diets put a strict emphasis on high-protein, high-fat ingredients from real animal sources.

While great for an otherwise healthy dog, this isn’t the best choice for a GI tract in need of remedy.

Hill’s Prescription Diet i/d Low Fat has the potential to help your dog sort out their GI issues and repair their digestive system. For any concerned dog owner who just wants the best for their dog, this is priceless.

A closeup picture of an extremely cute Yellow Lab.


We’ve just done a complete review of Hill’s Prescription Diet i/d Low Fat, doing a deep dive into some of the claims they make as well as an analysis of the ingredients and price.

This food was instrumental in helping Yuna with her digestive tract recovery. We recommend it to any other dog with digestive tract issues.

One other pro that we didn’t mention in the article–this food smells really good. I certainly can’t say that for most kibbles or treats!

And finally, Yuna seems to really enjoy this food. She always licks her bowl clean.

Anyways, you can find Hill’s Prescription Diet i/d Low Fat at the following link:

We hope this food helps your dog out as much as it helped our little Yuna!

Be sure to follow our Instagram and Pinterest for daily updates, more dog product reviews, and dog care tips!

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This Post Has 2 Comments

  1. Joan

    Thank you for your review! My 12 yr old Springer Spaniel, Magee was just diagnosed with chronic pancreatitis. My vet recommended this food and I was kind of freaking out about it after reading the ingredients list. Your explanation of the “whys” for these ingredients makes a lot of sense. He is currently on just chicken and rice, but I pick up the prescription food next week, and now I feel a little bit better about giving it a try. thank you! One question; do you give enzyme supplements to Yuna for her pancreatitis?

    1. Alexander

      Hi Joan, I totally get it! I felt the exact same way when Yuna was prescribed the food. Though I was skeptical, the food really made it much easier on her tummy. I hope it does the same for your Magee. As for enzyme supplements, we have not done that personally! It seemed that using this prescription food as well as some other medications was enough to keep Yuna’s pancreatitis at bay.

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