High Fat Diet Reduces Endurance
The Fitness Fixer
The Fitness Fixer

High Fat Diet Reduces Endurance

Racers eat all sorts of things hoping to extend endurance. A long history of drugs and supplements have been used from illegal to unhealthy to useless to good common sense nutrition.

Some racers load on unhealthful simple sugars hoping that will maximize needed carbohydrate stores called glycogen in the muscles. Others shun carbohydrates, even healthy needed nutrition in fruit and vegetables because they want to lose weight. A main effect of low carbohydrate diets is loss of muscle glycogen, quickly reducing size and water weight, giving the illusion of weight loss, and reducing exercise ability.

Another factor was identified in a study at Oxford University looking at using a high-fat diet. They found "stark reduction in physical endurance and a decline in cognitive ability after just nine days." Researcher found increased levels of a protein called the 'uncoupling protein' in the muscle and heart cells of rats on the high-fat diet. This protein 'uncouples' the process of burning food stuffs for energy in the cells, reducing the efficiency of the heart and muscles.

The study used rats, which have different nutritional needs than people. Previous rat nutrition studies led to higher than needed protein estimations, still believed by body builders hoping to build muscle through eating. This rat study seems to be in line with longitudinal dietary studies of human athletes who could not run as long on a treadmill or navigate as well through a maze. Dr Andrew Murray led the work at Oxford University. He stated, "We found that rats, when switched to a high-fat diet from their standard low-fat feed, showed a surprisingly quick reduction in their physical performance."

Primary Source: 'Deterioration of physical performance and cognitive function in rats with short-term high-fat feeding' by Andrew J Murray and colleagues. The FASEB Journal, 2009; DOI: 10.1096/fj.09-139691.
Copy of the paper: http://www.fasebj.org/cgi/rapidpdf/fj.09-139691v1.pdf

What they called a high fat diet was 55 per cent of the calories from fat. This may be less total fat than what I observe many people eating with fast food and junk food. Patients come to me proudly showing a food diary that they think is balanced because it lowers the total fat percentage of a recipe with lard by adding sugar. That is still the same high fat amount. Reduce your total fat, and keep your head not to avoid vegetables because they have a high percentage of carbohydrate. The percentage is high, not the total. If you have a one-dollar bill in your pocket and that's all, your pocket has 100% dollar bills, but not a lot of them.

In American Samoa, 93.5% of the people are estimated to be overweight since changing traditional complex carbohydrate low fat meals to Western imports of fatty food, junk sugar, and processed meat like Spam. In the Republic of Kiribati, another tropical island nation of the central Pacific, 81.5% are estimated overweight for the same reasons. Egypt began an increase of obesity when they began importing fast food. In the United States, over 65% of the people are considered overweight, related to considerable fat and high simple sugar from processed food with corn oil and high fructose corn syrup.

If your body chemistry, your temperament, medications you take, or economic situation pushes you to gain body fat from eating too much unhealthful food, eating less of it is still key to reducing overweight. I am not a nutrient biochemistry specialist, just a physiologist. For health and sports success over the long term, a working generality is to stop eating the fat and refined sugar of junk food, fast, food, and processed food, and many so-called "health-foods" which are expensive candy or over-processed products. Try an apple or favorite fruit and some walnuts for healthy exercise and endurance.

There are many components of health covered in the hundreds of Fitness Fixer articles already here, including how to fix injuries, stop pain, and improve sports and life abilities without expensive unhealthful sports food or drugs and medicines that reduce overall health.

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Dr. Bookspan is an award-winning scientist whose goal is to make exercise easier and healthier.