CARBOHYDRATE LOADING FOR DOGS.
Myth: Carbohydrate loading for dogs is a good idea. Fact: Carbohydrate loading does not work on dogs, and produces negative side effects.
1,000 years ago, everybody knew the earth was the center of the universe. 500 years ago, everybody knew the earth was flat. 50 years ago, everybody knew no man could break the 4-minute mile barrier. As the old saying goes, a little knowledge can be a dangerous thing, especially when based on false myths.
In his landmark book, The Meaning of Myth, the late Joseph Campbell revealed that myths are an essential part of our make up as humans. We develop myths to help us understand a chaotic and dangerous natural world full of mysterious events. In short, myths help us make sense of things we can't explain any other way.
Canine nutrition myths, ranging from silly to outright dangerous, thrive in the dog world. The reason these false belief systems have been so prevalent for so long is simple. In the absence of reliable information, any notion that seems to explain why something occurs makes sense, at least at the time. Over time, a myth, no matter how wrong it might be, is repeated so often that it takes on a life of its own. Finally, the myth becomes something that everybody "knows" is true, just as everybody knew the earth was flat.
Until the recent advances in sports medicine, human nutrition and performance were held hostage by
false myth. As a result, performance and health among human athletes were artificially limited by false beliefs just as performance dogs are today. For example, not long ago huge pro football players, who often lose 10 pounds in summer practice, were discouraged from drinking water during workouts because it would "cramp them up". Similarly, sports drink use was discouraged for the same reason. Of course, both notions are now considered out dated myths.
From time to time, PERFORMANCE DOG MAGAZINE takes on outdated myths by engaging in good-natured, but serious, debate on topics related to canine nutrition and conditioning. We'll examine published ads and articles to see if they provide up to date information, or continue outdated myths. There are no sacred cows here; anything published for fanciers - especially written to sell products - is fair game.
The goal here is simple -
to help you weed through myths so that you can make more informed decisions, which in turn helps you raise the performance and health of your dogs to new levels. The winner is not who presents a better case. The real winner, of course, is your dog.
The rules are simple. Each side of an argument follows basic debate rules. In other words, people have to support their points with something more than "everybody knows". It's the "everybody knows" mindset that begins and promotes myths in the first place.
The first myth and misinformation reviewed is by Mike Williams, who has written canine nutritional articles and a book entitled Stamina. Among Mr. Williams' repertoire of writings, we began with this article because
rarely does such a stark contrast between canine myth and scientific fact present itself. Mr. Williams' article and its primary myths are summarized below:
The Russians developed carbohydrate loading and used it extensively. The best way to carbohydrate load for humans is the depletion method, which involves withholding carbohydrate during intense workouts, then taking in ultra-high amounts of carbohydrates. Moreover, carbohydrate loading works as well and for the same reasons for canine athletes as it does on humans. During the last phase of carbohydrate loading, it's good to give boiled eggs and fiber.
Myth #1 The Russians Used "Carbohydrate Loading" Extensively.
Fact: Scandinavian researchers developed carbohydrate loading over 30 years ago. Respected researchers Drs. Astrad, Hultman and others are credited with the classical carbohydrate loading studies and the knowledge evolving from them. By the way, most dietary advances for athletes emanated not from medical doctors as widely believed (another myth!), but by sports scientists. Today, sports scientists like to be called exercise physiologists.
Whatever you call them, in 1967 these researchers began studying the effects of dietary manipulation on endurance exercise performance. Going into their experiments, it appeared from earlier studies that endurance performance was associated with the amount of glycogen stored in the muscle tissue. Glycogen is the chemical storage form carbohydrates take after you eat them.
To make a long technical story short, they stuffed extra carbohydrates into military soldiers and took muscle samples to see how much more glycogen this overeating seemed to yield. Then, they exercised these test subjects almost until exhaustion. They made several key discoveries. First, they noted the more carbohydrates test subjects ate, the more muscle glycogen their bodies tended to store. And the more muscle glycogen their bodies stored, the greater the endurance performance.
Second, researchers compared methods of manipulating diet to induce greater glycogen storage. One of their methods involved a depletion stage in which carbohydrates were withheld while the athlete worked out. After this depletion stage, a period of high carbohydrate intake occurred. This resulted in very high levels of muscle glycogen.
But as in most fields of science that evolve rapidly, new discoveries often make older beliefs outdated. This original carbohydrate loading study is just that - the first. But Mr. Williams is not aware that it is not the only study. Since then, many new insights have been gained into carbohydrate metabolism that reveals new and better ways of using carbohydrates to increase human performance.
Russian sport scientists, and American scientists who've traveled to Russia to learn first hand their sports medicine practices, reveal that carbohydrate loading was never the big deal it was in America. Americans have used carbohydrate loading much more than Russians, since the Soviets long ago realized the downsides to carbohydrate loading, especially using the depletion method.
Myth #2 The Best Way To Carbohydrate Load Is Using The Depletion Method.
Fact:
The 30-year-old depletion method causes a wide array of negative side effects, ranging from slightly uncomfortable to potentially dangerous. If you've ever personally withheld carbohydrates while exercising hard then stuffing carbohydrates, you've noted first hand the many unpleasant aspects to depletion.
Large fluctuations in fluid balance, diarrhea, elevations in stress hormones resulting in muscle loss, ketosis and other metabolic alterations. These negatives account for why the depletion method of carbohydrate loading has lost much of its appeal since its heyday in the 1970s.
A newer and much improved method of carbohydrate intake comes from an important study by Dr. Sherman almost two decades after the first carbohydrate loading studies. In a well-controlled experiment, Dr. Sherman discovered that athletes could achieve the same increases in glycogen gained during carbohydrate depletion method, while avoiding the serious drawbacks. After all, the depletion stage's accompanying muscle damage and other side effects often cancel out the increased glycogen advantages!
Dr. Sherman's protocol was deceptively simple, yet highly effective. Instead of going through a disruptive depletion stage, he simply had athletes increase dietary carbohydrate intake the last three days before an event with rest. The glycogen stores achieved were almost the same as with the depletion method, without the negative side effects. Little wonder why this method is now favored over the old depletion method.
Myth #3 Carbohydrate Loading Is A Good Idea For Dogs.
Fact: The notion of ultra-high carbohydrate intake - and carbohydrate loading -for human athletes is undergoing serious re-examination. Recent thinking among a growing number of experts is that
excess carbohydrates can inhibit the burning of fat stored in the body, and may also increase excess fat storage, and possibly even limit endurance.
Here's why, they say. Even very lean athletes have enough body fat for back-to-back workouts already stored in fat tissue. But excess carbohydrate intake produces excess insulin, the hormone produced in response to carbohydrate intake. Excess insulin blocks the use of stored body fat. Therefore,
excess carbohydrate intake, which causes excess insulin, tends to inhibit fat utilization. In turn, this is a leading cause of the "running hot" syndrome.
In other words, an athlete's hungry muscles can't "get to" stored fat to use for energy.
So the body uses more carbohydrates, which produces more lactic acid. And because of the overabundance of carbohydrates, excess lactic acid is produced and the "running hot" syndrome comes into play.
In humans, recent studies suggest a more balanced approach to carbohydrate intake may work better. Some experts believe that ultra-high carbohydrate intake at the expense of proteins and fats isn't what it was cracked up to be in the old days. This push and pull of ideas is at the heart of science. At any rate, it's fair to say carbohydrate loading is being rethought, and is not the rage it was in the early 1970s.
No Guesswork on Dogs
The scientific record of carbo loading on dogs is clear - it does not work, and can produce serious negative side effects. A good deal of research has been conducted in this area. In the 1970s, Dr. Kronfeld conducted several studies and found that
higher protein and fat diets appeared to enhance sled dog performance better than higher carbohydrate content diets.
Building on earlier work, Dr. Reynolds and others at Harvard, Cornell and Bern Switzerland tested various diets on well-conditioned sled dogs and retrievers clearly revealed that dogs taking in higher fat and protein intakes had better performance compared to dogs on high carbohydrate intakes. The reason for
this, researchers state, is because during endurance exercise canine muscle tissue relies heavily upon the breakdown and burning of fat for energy, and an overabundance of glycogen and carbohydrate oxidation may block fat burning.
They found when you give excess carbohydrates to your dog, it may actually reduce endurance performance. That's because the extra glycogen added with carbohydrate added with carbohydrate loading gets used up faster than normal, and as a result, creates more lactic acid. In other words, the ultimate energy source in the dog - fat - can't be used because excess carbohydrates actually inhibit or block this vital energy process.
Even ultra lean dogs have enough fat stored in muscle and blood stream and body to supply the energy for daily back-to-back workouts. But too much carbohydrate and too little fat in the diet means the fat never gets a chance to kick in.
High Carbohydrates = High Lactic Acid
Here's the basis for why moderate to high fat intakes are superior to high carbohydrate intakes, as presented by researchers. When carbohydrates are burned for energy, one of the by-products is lactic acid. Lactic acid is actually a two-part molecule. Only 1%, by molecular weight, is acid (H+). The other 99% is lactate (L-) which is a base. A base is a substance that buffers acids.
Lactate and acid immediately dissociate (split) from each other when produced.
It is the acid (H+) that causes the burn and pain associated with lactic acid because like all acids, it lowers pH, in this case in the muscle. Lowering pH shuts off key muscle energy enabling enzymes from doing their jobs. Because these enzymes are "turned off", the ability to keep contract muscle fibers is greatly reduced. Therefore, it is the acid part of lactic acid that causes the problems, not lactate, per se.
The newest studies reveal that of the lactate produced, about 75% is used directly by the muscles as fuel; the remaining 25% travels to the liver to be converted into liver glycogen, or glucose. That's because in addition to its ability to neutralize acid, lactate is also an active energy source used by
muscle tissue.
But the more glycogen burned for energy, the more acid (H+) produced. And remember that it's acid (H+) that causes the problems - not lactate. To a major degree, the burning of excess stored carbohydrates occurs at the expense of burning free fatty acids (fat) for energy. This is because elevated insulin levels associated with carbohydrate loading tend to inhibit the
mobilization and burning of fats.
Myth #4 Assuming Carbohydrate Loading For Dogs Is A Good Idea, Then The Depletion Method Is The Way To Go.
Fact: Carbohydrate loading for dogs, especially the depletion method promoted by Mr. Williams, is a wrongheaded and outdated idea. The depletion phase creates serious side effects ranging from sharp increases in stress hormones resulting in a breakdown of lean muscle, to cell membrane damage, plus a reduction in oxygen carrying capacity and "running hot".
For dogs attempting to "make weight", depleting carbohydrates carries an additional penalty - severe and often unpredictable weight fluctuations. It is common for dogs to lose and gain 2-4% of their total body weight in water shifts when they deplete, then restock carbs. This amounts to a total weight gain and loss of 3-5 pounds for a 45-pound dog. Trying to make weight with such large shifts in body fluids makes it very difficult to predict body weight in events like weight pulling.
So aside from the documented negative metabolic effects of depleting carbs, attempting to make weight becomes even more challenging.
And if body weight exceeds the weight class, which is typical using Mr. Williams' method, then water is often withheld from the dog to reduce. This often results in dehydration, reduced performance and heat stroke.
Myth #5 Taking In Super-High Carbohydrate Food Is A Good Idea Before A Contest.
Fact: This is a bad idea before events, and is likely to make dogs "run hot".
By now it's clear - carbohydrate loading is a bad idea for dogs, especially the depletion method presented by Mr. Williams. To make matters worse, during the depletion stage he advises feeding boiled eggs and fiber to dogs that have never received either previously.
Clearly, this out-of-the-blue introduction of foods can cause real GI (gastrointestinal) distress ranging from constipation to diarrhea, or both, directly before a competition. How could Mr. Williams, without offering any supporting evidence or validation other than essentially the old "everybody knows" line of reasoning expect performance dog fanciers to accept his views as reliable-or even safe.
In summary, carbohydrate loading for dogs is a bad idea that is more likely to inhibit performance than increase it. Scientific and real world research from around the world proves this fact time and time again. Moreover, using the outdated depletion procedure presented by Mr. Williams produces even more negative side effects and is much more likely to make dogs "run hot".
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