DR. MIRKIN ON SUGAR. WHY?
Why You Should Eat Sugar During Prolonged Exercise
By Gabe Mirkin, M.D.
The limiting factor to how fast and intensely you can exercise in events requiring endurance depends on how quickly you can get sugar into muscles during exercise.
Since sugar requires less oxygen than fat and protein do, keeping sugar in your muscles as a fuel for exercise reduces your needs for oxygen and helps you to exercise faster and with more intensity in endurance events.
You can markedly improve performance in endurance sports by eating just before your event begins, and starting to eat and drink soon after you start exercising.
During exercise, muscles draw sugar rapidly from your bloodstream. The energy for your brain comes almost exclusively from the sugar in your bloodstream. When blood sugar levels drop, so do brain levels and you feel tired and have difficulty coordinating your muscles.
However, there is only enough sugar in your bloodstream to last three minutes at rest. To maintain blood sugar levels, your liver has to release sugar into your bloodstream. But there is only enough sugar in your liver to last about twelve hours at rest and far less than that when you exercise.
When muscles run out of their stored sugar supply, it hurts to exercise and the muscles become difficult to control.
DON’T DEPEND ON HUNGER
Hunger during exercise is a very late sign of not getting enough calories. You can increase endurance by starting to eat anything or to drink fluids that contain sugar as soon as you start to exercise. This will give you far greater endurance than waiting to take food after an hour of exercise or when you feel hungry.
WHAT TO EAT AND DRINK
All carbohydrates are single sugars, or sugars bound together in twos, up to thousands and millions. Before any carbohydrate can be absorbed into your bloodstream, it must first be broken down into single sugars.
Human intestines do not permit combination sugars to pass into the bloodstream, so the most effective way to increase endurance is to take sugar-containing foods and drinks during prolonged exercise.
SUGAR AND CAFFEINE
Sugared drinks are absorbed faster than sugared foods, and caffeine increases the rate of absorption of sugars by up to 25 percent.
Higher doses of caffeine are not more effective than the low doses found in a cup of coffee or a couple of soft drinks, so athletes often take sugared, caffeinated soft drinks such as Coca Cola or Pepsi. Very high doses of caffeine can cause irregular heart beats and kill you, so you should never take caffeine pills.
During a competition you should try to limit your intake of caffeine to not more than the equivalent of three cups of coffee or nine cups of soft drinks (one cup of coffee usually contains the same amount of caffeine as three soft drinks or two cups of tea).
IN EVENTS LASTING MORE THAN TWO HOURS, EAT FOOD
In very long events, you cannot get enough calories from drinks. You have to eat solid food. Good sugar-containing foods include sugared whole grain bars or almost any type of sandwich.
EATING BEFORE COMPETING
Before competitions, knowledgeable competitive athletes cut back on their training load and eat a little more of foods that contain carbohydrates. This increases the amount of sugar stored in their muscles at the start of their event, but it is far less important than what they do during their event.
AVOID SUGAR WHEN YOU ARE NOT EXERCISING
A high rise in blood sugar causes sugar to stick to the outer surface of cell membranes. Once there, sugar can never get off and is eventually converted by a series of chemical reactions to sorbitol which destroys the cell and can damage every cell in your body. All of the horrible side effects of diabetes are caused by sugar sticking to cells.
You do not have to be diabetic to suffer nerve, brain and blood vessel damage from a high rise in blood sugar. Therefore what is good for you during exercise can harm you at rest.
Contracting muscles can draw sugar from muscles without requiring insulin, but resting muscles cannot. Therefore, during exercise, a high sugar intake is usually harmless, but when muscles are not contracting, blood sugar levels can rise very high and damage every cell in your body.
Dr. Pinna says:
Dr. Mirkin is a very bright physician and always backs up his suggestions with studies that support his arguments. But, this article which advises the use of “sugar” to increase endurance and speed is not very logical.
Plus…There are No Studies to back it up.
Prior to five thousand years ago, more or less, there was no such food as “Sugar.” Sugar is a molecule made through the processing of plants, such as sugar cane and sugar beets.
“Sugar” does not exist in Nature! The closest natural food is honey, which is composed of “Glucose.”
NO ANIMAL EATS SUGAR. Every animal on this planet, including the fastest mammals, such as the Cheetah, runs, fights, kills, and defends itself without consuming sugar!
If every animal can survive without sugar, in the most vital situations, where they must kill or be killed, why do humans need sugar? They obviously do not.
SUCROSE
The term “SUGAR” refers to a large group of molecules, such as GLUCOSE, FRUCTOSE, SUCROSE, MALTOSE, etc. The “Sugar” to which Dr. Mirkin refers, is called SUCROSE.
It is made in factories from plants. The form humans use, crystalline sugar, is never found in nature.
SUCROSE is a molecule composed of two simple sugars, called GLUCOSE and FRUCTOSE.
Here is an excerpt from Wikipedia concerning the metabolism of SUCROSE:
“In mammals, sucrose is readily digested in the stomach into its component sugars, by acidic hydrolysis. This step is performed by a glycoside hydrolase, which catalyzes the hydrolysis of sucrose to the monosaccharides glucose and fructose. Glucose and fructose are rapidly absorbed into the bloodstream in the small intestine.
Sucrose, as a pure carbohydrate, has an energy content of 3.94 kilocalories per gram (or 17 kilojoules per gram).
When large amounts of food that contain high percentages of sucrose are consumed, beneficial nutrients can be displaced from the diet, which can contribute to an increased risk for chronic disease.
It has been suggested that sucrose-containing drinks may be linked to the development of obesity and insulin resistance. Most soft drinks in the USA are now made with high fructose corn syrup, not sucrose. HFCS 55 contains 55% fructose and 45% glucose.
The rapidity with which sucrose raises blood glucose can cause problems for people suffering from defective glucose metabolism, such as persons with hypoglycemia or diabetes mellitus. Sucrose can contribute to the development of metabolic syndrome.
In an experiment with rats that were fed a diet one-third of which was sucrose, the sucrose first elevated blood levels of triglycerides, which induced visceral fat and ultimately resulted in insulin resistance.
Another study found that rats fed sucrose-rich diets developed high triglycerides, hyperglycemia, and insulin resistance.”
CONCLUSION
SUCROSE is bad, no matter how or when or why you take it!
I cannot understand why any physician would recommend sucrose for any reason.
HIGH FRUCTOSE CORN SYRUP
This poison is found in most sweet drinks.
The manufacturers are paying companies to have high profile doctors write articles that promote the use of sweet drinks…
Think about it…
Dr. Pinna appears to have overlooked some aspects of metabolism as it pertains to endurance athletes/activities. Sugar is critical in supporting/facilitating high performance endurance sports. Every athlete that has performed at near maximal effort for an hour or so with out carbohydrate supplementation, preferably some form of sugar, has experienced what they call “bonking,” where the body runs into a very severe power decline, probably something approximating a power reduction of 50-70%!
Virtually everbody’s bodys carry enough fat to supply all of their energy needs for duration of this type of activity.
The problem is that at lower effort activities, the body uses fat as the primary source of energy. As intensity increases, the body demands ever increasing amounts of sugar to produce the energy. At the highest levels of effort/activity, the body can can consume its total store of sugar in the muscles, blood and liver. When that happens, one bonks.
I have 20 years of high intensity cycling experience plus additional decades of other sports and manual labor that bear this out. My greatest cycling performance has always involved 1 gram/minute, or more, for the duration of the activity. My experience bonking has only occurred where the sugar/carbohydrate consumption were comparatively low, such as ~1 gran/4-5 minutes, or less.
So your point about mammals and humans historically not consuming sugars in the pure form, as against complex carbohydrates, is true (other than honey). However, that fact does not negate the performance enhancing ability of sugar. What it does illustrate is simply that the lack of availability of simple sugars capped our long endurance physical performance well below what is possible.
I don’t have the specific biological/physiological explanation for the role of sugar in human & mammalian energy production, but that is be well understood/documented in the scientific world.
Dr. Pinna says..
The “Biker” is obviously Dr. Mirkin, and he should not
be so shy. He is a highly respected Clinician and
Educator for the Layman concerning medical topics.
The issue here is whether SUCROSE is necessary
for maximum effort of any animal in acts of endurance.
No studies have proven that it is.
The “ANECDOTAL”evidence presented by “Biker” would never be accepted by any scientist. Only studies comparing a “Test Group” (one using sucrose) and a “Control Group”
(one not using sucrose) wherein both do the same
activity would be considered.
Most medical scientists would not even consider one
such “Study” sufficient, and any competent medical
scientist would conclude: “More Studies are Needed.”
Any human who has been in the forest or jungles has
seen mammals, reptiles and birds fight with such
ferocity when they are being attacked, that no human
could possibly expend an equivalent amount of energy
in any sport.
That energy comes from the use of every muscle fiber
in their body spurred on by a totally excited nervous
system. NO HUMAN WILL DO THIS IN A SPORT!
Their glucose and fructose is used in anaerobic
metabolism and is found in the liver and muscle
glycogen. GLUCAGON AND EPINEPRINE are the two hormones
which release these sugars from the stores in
their muscles and liver.
Thus if any human athlete wants to exert himself
to the fullest, he needs no SUCROSE which must first
be broken down into GLUCOSE and FRUCTOSE in the
GI TRACT, BUT RATHER HE NEEDS EXTREME EXCITEMENT
OF HIS NERVOUS SYSTEM–SUCH AS WHEN HE THINKS
HE WILL BE KILLED BY AN ENEMY.
Only the Roman Gladiators were faced with this challenge.
I guarantee, they were not sucking on a sweet drink
when they fought to the death.
I assure you that I am not Dr Mirkin and am quite real. See my drivers license:
http://www.facebook.com/photo.php?pid=859438&l=82b754cc0d&id=1133080869
Ironically we share the same first name, and you can see my initials in my email address.
Dr. Mirkin and I were addressing endurance activities (“The limiting factor to how fast and intensely you can exercise in events requiring endurance depends on how quickly you can get sugar into muscles during exercise.”). You are referring to much shorter periods of activity. Very short maximal exertions are anaerobic, such as the 100 meter dash, relying solely on ATP, but for high intensity activities over 60 minutes, serum glycogen & muscle glucose can be driven to a very low level, resulting in a “bonk.” Just Google the words
bicycle bonk.
I was not intending to provide scientific proof to an arrogant Dr., but simply provide layman’s experience which corroborates Dr. Mirkin’s comments.
There are plenty of scientific literature/studies on the web for that. For example, http://www.ncbi.nlm.nih.gov/pubmed/20299609
By way of comparison, I spent 2 years in collage in the pre-medicine major before switching to computer science, so talking down to me doesn’t sit too well.
All of the way back in the 1980′s or early 1990′s the scientific studies on endurance runners and cyclers were completed, comparing supplementation with water vs carbohydrate drinks and the results were very clear as to the benefit of the carbohydrates in the these longer, higher intensity activities.
The general benefits of carbohydrate supplementation in long distance running and cycling was settled about 20-25 years ago. Just Google the words:
cycling endurance glucose
for a long list of web pages discussing the finer points supplementation.
I dare you to publish this comment.
I have written and published a reply to the
comment above.
It is titled “SUGAR, CARBOHYDRATES AND ROBBING THE PUBLIC.”
Very few people understand the biochemistry of sugars
and glycogen. Even doctors trained in biochemistry
have a tendency to forget the way FRUCTOSE
is metabolized in the liver.
My new article is an attempt to simplify this biochemistry.
I give an example of a bird that flies across the Pacific
Ocean non-stop for nine days!
That bird does not complain about “Bonks.”
Humans complain about everything, including sports.
When sports are no longer fun, you are losing your
animal nature, which we call courage.
Whoever cannot handle a sport should take up sewing…