Metabolic Gridlock


Human energy metabolism is a complicated process whereby nutrients are converted into a usable form of energy called ATP. There are three nutrients involved in this process which are carbohydrates, fats, and to a lesser extent proteins. Each nutrient is harvested for the energy found in the molecular bonds and is disposed of in the form of carbon dioxide (CO2). This process occurs in each cell with approximately 70-90% of ATP generated by the mitochondria, an organelle responsible for energy production.

The physiology of the mitochondria dictates that a shift occurs in fuel usage depending upon the state of the organism. During fasting states, the mitochondria use fats to produce ATP while during fed states the mitochondria use carbohydrate. Proteins are not a preferred fuel for ATP production although some conversion will occur. When the fuel for ATP production is in proper proportion the process can freely switch between fat use and carbohydrate use. But when an excessive amount of fuel is made available the mitochondria becomes inflexible and can no longer switch freely between sources.

When this occurs, the body enters a state of metabolic gridlock as fuel piles up and the mitochondria can no longer meet the demand. The consequences of metabolic gridlock include increased oxidative stress, greater fat production, and insulin sensitivity which are the hallmark of metabolic syndrome. For those not familiar with metabolic syndrome, it is a set of maladaptive physiological conditions that increase the risk of cardiovascular disease, cancer, and type II diabetes.

So what causes metabolic gridlock? An over-abundance of fuel is the culprit, especially carbohydrate. The western diet most of us follow is high in starch and processed sugar which has a profound effect on blood sugar levels. Since the conversion of carbohydrate to ATP is favored, high levels disrupt the ability of the mitochondria to freely switch fuel usage. A couple high carbohydrate with high fat and metabolic gridlock is inevitable.

How can metabolic gridlock be avoided? By controlling energy intake and increasing energy expenditure. It is, however, not as simple as calories in vs. calories out which is a common practice for those seeking to improve diet. Calorie counting seeks to quantify the amount of energy we put into our bodies, but it is based off a century old theory. What is now known is that calories vary from food source to food source and from person to person. Therefore, the calculations of caloric need don’t necessarily reflect the need or the output.

The best approach to avoiding or correcting metabolic gridlock is by first controlling the quality of food that is eaten and second increase physical activity. Primarily eating fruits and vegetables coupled with lean protein sources all while avoided high starch foods and foods with added sugar can improve the quality of the diet. A second dietary practice that is helpful is low caloric cleansing programs. Natural cleanse programs that emphasize fresh fruits, fresh vegetables, and water can help the mitochondria catch up with the fuel backload and alleviate gridlock.

Physical activity can be very useful for avoiding/correcting metabolic gridlock because of the role it plays in carbohydrate metabolism. As mentioned earlier, carbohydrate use as a fuel source is increased with feeding. This is usually mediated by insulin which increases cellular uptake of carbohydrate into the cell. Exercise can increase carbohydrate use as a fuel without inducing insulin. This allows first for blood sugar to normalize and second for excess energy to be cleared by the mitochondria. The overall effect of physical activity is to alleviate metabolic gridlock.

Coupling high-quality nutrition with exercise can greatly improve the ability of the mitochondria to be flexible with fuel choice and can lead to body composition improvement. Thank you for reading The Perpetual Athlete blog and continue to check for more entries, as well as other health related materials.

Photo taken from Metabolic Inflexibility: When Mitochondrial Indecision Leads to Metabolic Gridlock by Deborah M. Muoio (Cell 159, 2014).

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Bill Fredericks

Bill Fredericks

Bill Fredericks

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