Doughnut Hole

Think of the Doughnut hole, the space filled with air going from the top to the bottom of the Doughnut. Now place your finger in the Doughnut and wear it like a ring. Is there any question that the hole is NOT the Doughnut? Yet without the Doughnut, there would be no hole. Placing your finger within the hole doesn’t really place it within the Doughnut. Your finger is outside the Doughnut but within the Doughnut hole.

Go ahead if you must. Eat the Doughnut.

Now think of your body. Doesn’t it too have a hole through it? It starts at the mouth and ends at the anus. Food goes in, and something that doesn’t look like what you ate comes out the other end. This process is true for your horse though many only see money go in and something that doesn’t look like money comes out the other end.

We can all agree that a tube runs through us much like a Doughnut hole (or some people think of it as a road tunnel going under a body of water with cars going through it). But, can we also agree that what we eat is not inside us? Like the finger within the Doughnut hole, food is within the tube called the digestive tract and NOT within our body.

I get it – we all have a tube running through us.

The Magic of Digestion

The magic of digestion is the process where the food we eat breaks down into small parts so small that no machine can see them yet. These small parts are molecules absorbed through the skin of the digestive tract tube into the body. Just like the coffee that filled the hole gets soaked into the Doughnut.

I did say the “skin” of the digestive tract because it is like the skin on the outside of the body, only different. Our skin keeps dirt and germs out unless the skin becomes damaged. If cut, scraped, bruised, burned or otherwise broken, then the bacteria on our skin and even the cloud around us (yes, you CAN smell trouble coming) will enter the body when it is not supposed to. Our bodies fight the infection using the immune system and a building and repair system to close the wound. And this all happens without thought.

The skin of the digestive tract also defends against invasion with two mechanisms. The first is a one-cell layer thick covering with very tight junctions between the cells, and the second is a layer of mucus. The tight junctions keep things physically out of the body, and the mucus traps foreign and unwanted foods and carries them out without them being absorbed.

If the mucus layer is destroyed, the underlying cell layer becomes exposed to unwanted material. Several things can do this, from foods that are not friendly to the horse to antibiotics to medication to prevent ulcers.

Suppose the tight junctions between the layer of cells lining the digestive tract become inflamed because of foreign material. In that case, the tube becomes leaky, allowing unwanted foreign material to get into the body like a cut to the skin. Unfortunately, it also allows what is inside the body to leak out. Overall, what is supposed to get in to give us energy and nutrition is used immediately to build and repair. However, over time this process can eventually scar the digestive tract to a point where it no longer works.

I thought all goats, oops, I mean proteins, were good.

Good Protein Versus Bad Protein

Next time you eat food or feed your horse think about the Doughnut hole and the efforts the digestive tract makes to keep bad things out while also allowing good things in. For example, water is always allowed in and passes freely into the body one molecule at a time. Likewise, good protein breaks down into an amino acid molecule, which is absorbed into the body and then reassembled into the protein you or your horse needs.

Did I say “good protein?” Yes, there are bad proteins and plenty of them. The mucus layer traps them and carries them away. But if the layer is compromised and the bad proteins contact the cells, then they damage the cells, cause the gut to leak and mount an inflammatory response.

Where can these “bad proteins” be found? They are in all grains, bran and beans. It is why I am shouting from the top of my barn – “Stop feeding grain to horses!” It is why the signs of grain intolerance in horses are eliminated within 1 to 2 weeks of removing all grain from the diet. See previous blogs, especially last week’s blog titled “No Sweat,” where non-sweating horses start to sweat after the removal of grain. It is also why some horses become fat when looking at a bucket of grain while other “poor keepers” can’t gain a pound when fed a bucket of grain twice a day. It explains bad behavior, especially a poor work ethic (fusses when groomed, bucking when ridden, unwilling to load into a trailer). And, of course, colic, skin allergies, Cushing’s disease, metabolic syndrome, dropped pasterns, tying up, and assorted other ailments that have exploded in incidence over the past 40 years.

I should know because most of these problems did not exist when I started with horses in 1973. Some were not even in the veterinary textbooks, not because we didn’t understand them, but because they didn’t exist. There were few grain stores and no fancy, four-color bags filled with every kind of grain mix and printed with words you couldn’t even pronounce.

Keep reading the other blogs here on Horsemanship Nutrition. In the meantime, take the 2-week no-grain challenge and think of the Doughnut hole. You will discover a new horse in your barn, and you will like what you find.

 I want to try the Two-Week No Grain Challenge.

Back to top


Leave a Reply to geofftuckerdvm

This site uses Akismet to reduce spam. Learn how your comment data is processed.

  1. My 2 horses have been grain free for 6 months and are doing great. Has changed there attitudes completely. Just soybean meal and Timothy/alfalfa hay cubes

    I recently got a 6 year old that was on some kind of pellet and sweetfeed and had no energy so I switched her to my other horses diets and now her energy levels are almost too high now.. any suggestions ? My other horses seemed to mellow out and she seems more on the edge

    1. At 6 years of age this horse probably does not have a severe protein deficiency. There is no test to determine amino acid levels in the horse but if she is urinating a lot and the urine has a distinct ammonia smell then the horse is converting the protein into sugar. This is what happens to excess protein in the diet and is why the Atkins diet ultimately failed in humans.

      Remove the SBM in the 6 year old and observe for a week or two. Then (assuming he is a full size horse) add about ¼ cup of SBM per day. Adjust this up or down as needed by your observations.

      Please come back here to let all know how this worked.

  2. Doc T, One of my horses has been on the no grain challenge for almost a year, and a new horse was started 3 months ago. Both are doing excellent! Thank you for the Nutrition Course. Cindy

  3. This post reminded me of my old Thoroughbred polo pony, Bobby, who you treated 35-or-so years ago following the loss of his pasture mate to a broken leg. Bobby went into a deep depression for a few weeks, very slowly regaining interest in life. He had always been an easy keeper, especially for a TB, like your description of gaining weight by looking at a feed bag. But after this event he kept losing weight and condition no matter how much feed I poured into him. You suggested stopping corn-based feed and switching to beet pulp-based feed and hay. That switch took 10 years off his appearance. He blossomed, got fat and shiny again, and regained his old personality and lived until the age of 25.

    1. Thanks Kenn for stopping by with this memory. Corn, corn syrup, corn oil all affect the gut lining of humans. When I lived in upstate New York with you back in the 1980’s there was nothing better than stopping along the road and picking some fresh corn on the cob and baking it in its husk on the grill. Slathered in fresh butter, there was nothing that said summer more than this with some fresh grilled burgers at one of the gorges in Ithaca.

      But it was seasonal. It was not day after day with corn stored in bulk where molds could grow then mixed with grain byproducts such as wheat middlings. Our guts had a chance to heal between October and August from the damage it did.

      Good to hear from you my friend and fun for a moment to go back….

    1. Thank you for posting this and letting others know of your success. I’m sure he is happier now!

  4. What about elderly horses that are no longer properly masticating baled hay? Can a horse live on soaked alfalfa cubes and still go without grain?


      Adding soybean meal is what will restore the amino acids reservoir. But feeding them becomes a management issue – to find whatever is needed to get the food from the ground to the stomach. At this point it makes you realize how important the teeth and the swollowing process is. Remember the primary purpose of chewing is to create a swallowable bolus of food. Ask any man who gulps his food (lol, I’m one of those). They have no trouble keeping weight on. But my client’s husband with a stroke could no longer swallow and died from starvation.

      Work on the teeth and work of the feeding management. Add protein (alfalfa and soybean meal). Adding grain only adds fat but the underlying problems from the gut inflammation will ultimately get to these older horses. Of course there are exceptions and from some genetics, there are horses (and people) who live a long time not caring for what they eat. And honestly for many horses, they die long before old age due to the gut inflammation. They age is actually selecting for these hardy individuals.

      Also remember Coolstance (shredded coconut meat) to add non-inflammatory fat / calories).

  5. Wonder where you got that ‘doughnut” idea…. had some last weekend…. I know, I know… no more! But it was still warm, and that donut hole…. massive! Thanks for all your explanations!

    1. I have always looked at the digestive tract as a doughnut hole. Dr Gundry in his book The Plant Paradox looks at it as an automobile tunnel under the water. The cars are IN the tunnel but NOT IN the water.

      LOL about the doughnuts you ate – warm, soft, good smell…..

  6. Geez Doc T, rethink what we are doing? What planet did you come from? (LOL) Thanks for the article. Makes sense. So many things we “do” because somewhere someone did, the fad caught on “good” or not….. That’s why I LOVE your visits, Kaye and Molly the 3 legged pony and friends

    1. Hi Kaye and crew! Allow me to post a plug for you.

      Go to Molly The Pony right now and learn about this remarkable story of how a pony with 3 legs and an artificial limb brings joy and comfort to so many people. Please donate to their foundation.

  7. i started your no grain diet and my horse was so unhappy so i started giving her rice bran and timothy grass pellets is that ok. She is not the best hay eater i do believe she has been a non sweater her wholel life and she is 15 years old. even raced this was.

    1. Jody – It is hard for many people to be the parent or leader. Often the children or people show their displeasure in the decision the parent or leader makes.Evidence that I am right can be seen from the neighbor’s house with children to the White House.

      Often what is most bad for us gives the loudest objection when removed. This is commonly seen in addicted people when the addictive substance is removed. Look at your horse’s displeasure as a sign that the grain has made the horse feel good, like the 1000 calorie dessert, but know that it really isn’t good causing inflammation, increased weight, non-sweating, and so much more.

      It’s time to lead Jody. It’s only 10 to 14 days. And I promise you that in the future I will try to explain why grain, including all brans, are not helping our friends. Let us all know how you did. With tough love, Doc T

  8. Well, this is interesting. Keep writing doc. Do you feel this way about forage first grains, such as equine SR. Can they really live on hay alone?

    1. Hi April – be sure to read all the ingredients. I have seen many hay extenders with inflammatory ingredients such as wheat middlings.

      Forage First uses all hay ingredients in various mixes. They do use fungicides and other means to create a more robust product so these hays are not organic. Purina’s Equine Senior I find interesting in that on their web site, there are no ingredients listed. They say some general items but not specific things. This is suspicious and non-transparent. Go to Crypto Aero’s site for the opposite.

      What I am discovering is that many feeds have ingredients that cause gut inflammation such as grain, bran and oils. Horses have lived for many years without any of these needed. We all admire the “wild” horse with their sleek looks galloping across the plains yet we all struggle with our horses with: poor hair coat, poor hooves, poor top line, lameness, skin disease, organ dysfunction (metabolic syndrome, Cushing’s, insulin resistance), non-sweating, poor work ethic, unhappy and fidgeting for grooming and girthing or trailer loading. All of these seem to be resolving in horses that go grain free eating nothing but grass and hay. There are some exceptions such as horses older than 25. But today I saw a 28 year old I got off of grain and onto protein (whey) a year ago. I literally could not recognize this horse because the “old” look was completely replaced with a glossy coat covering muscles. He had become unrecognizable to me – a completely different horse.

      So YES, they can live on hay (and pasture, raw salt & water) alone. They have for way before humans started to do what they think is best. By the way, how is this working for humans?? Obesity is epidemic as well as heart disease, kidney disease, mental disease. If we can’t fix ourselves with what we are doing, how can we think we know what to do for a horse or any other animal. It’s time to re-think things and that is what I am doing.

      As always, thanks for reading and commenting.

    2. I have 4 horses of various breeds (QH, TB, MFT) in my barn and all are totally grain free. Grass hay, pasture when available, salt and water are all they get. They have never looked better. No more chronic colic, ulcers, nervous, hyper behavior or big grass belly. Even my vet commented on how good they look. Oh, must mention that 3 of them are currently on 1 pound of Soybean meal per day per Dr. Tucker’s recommendations.

      1. Thank you Sandy for sharing this with all of us. You are helping others to overcome their fear of changing how they feed their horses.

  9. I think the idea of no grain has credence. We’re using a local mix called Crypto Aero. I will revisit the ingredients although they eat mostly hay.
    I appreciate the reminder. I’m gluten intolerant and am healing a leaky guy.
    See you or Mellissa in 5 months.
    Love, Callie, Dude and Joanie

    1. Joan – all grains can cause inflammation in all horses to a degree. Some do better than others. Corn and wheat middlings are the worst offenders but there are many others. The Crypto Aero owner tries to avoid many of these (we know the owner) and she is very proud of her bag too! Here are the ingredients: Whole oats, timothy hay pellets, alfalfa hay pellets, sunflower seeds, green peas, yellow peas, rice bran oil, ground flax, rose hips, green cabbage, papaya, algae, organic yeast, anise, fenugreek.

      My suggestion here is if you have a horse exhibiting any signs of leaky gut / gut inflammation, eliminate everything except grass, hay, raw salt and water for 2 weeks. After the gut has quited (and it will take up to 6 weeks to fully heal), slowly add 1 product at a time and observe for a few weeks. I think Crypto Aero will work with most horses but there will still be a few that some of the ingredients will affect. Each horse will be different and you must write down all observations.

      More information will be coming in the next few weeks about grains, bran, legumes, and oils. I don’t have all the answers and for horses, the data is still slim. All the new info is from human research and that is controversial. But from my standpoint as I go from farm to farm, almost all horses being fed anything but grass and hay show some sign of inflammation and chronic protein loss. Stay tuned.