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How your Body Converts Foods into Energy

Other than pure honey, fruits energize your body more quickly than any other natural food. Sure candy bars or sugar and caffeine laden sodas will ratchet your energy level up fast, but it’s zoom … splat. You’re left with less energy after a temporary sugar high. A candy bar versus a piece of fruit is like the difference between a flash bulb or an incandescent bulb that provides long term steady light.

Unlike foods infused with loads of processed sugar, fruits give you a significant boost in energy that lasts a much longer time. As an added bonus, you do not come crashing back down to Earth like the unfortunate Icarus after he flew too high, too fast.

Fruits work magic in your body.

The reason a chocolate bar cannot provide you with same sustained energy an apple can (without the terrible withdrawal symptoms) has to do with the body’s conversion process of the fruit’s carbohydrates into usable units of energy.

Although during the digestive process some of the fruit’s sugar is absorbed into the body through the roof of the mouth after being broken down by the pre-digestive saliva; the great bulk of the fruit travels on towards your stomach. There, most of the fructose passes through the stomach’s walls and is transported to the liver.

Whole fruits contain significant amounts of fiber. This fibrous mass continues onwards to the small intestines where additional nutrients are absorbed. The remainder of the fiber is pushed into the colon and finally passes through the alimentary canal as waste.

A storehouse of energy

The human body stores sugar that isn’t immediately converted into energy. That’s why concentrated, processed sugar shocks the body and creates an energy spike. The processed sugar is like too much water spilling over the ridge of a reservoir. This is especially true if concentrated sugar, such as that found in sodas and candies, is ingested without the fibers, vitamins and minerals that accompany sugar in its natural state. It places a measurable strain on the functions of the liver and pancreas.

Repeated assaults on the liver and the pancreas-especially from the sugars in alcohol-can lead to chronic liver diseases, pancreatitis, diabetes and sometimes liver or pancreatic cancer.

Fruit’s sugar in the body prompts the glucose level to rise in the blood. This creates a reaction in the pancreas releasing a small amount of insulin. Insulin transports the glucose to cells through receptors that act like switches in a train yard sending the glucose on one of three paths: about half is utilized by the body for immediate energy; roughly ten percent is routed to muscle tissue and the liver and stored as glycogen; and the remainder is converted to fat (triglycerides and cholesterol) and stored for future use.


The body uses oxygen to burn the fuel, glucose. This usable energy is known as Aerobic Glycolysis. The energy derived from the fruit is chemically attached to a molecule called ADP (Adenosine Di Phosphate). This results in the conversion from ADP to ATP (Adenosine Triphosphate).

All this chemistry occurring in the body acts like a fuse being inserted into a tiny firecracker. Upon demand from the body the ATP fuse is lit releasing that amount of energy from the primed molecule. The cycle is complete when the ATP is used by the body thus converting its chemical make up back to ADP. The entire process is known as respiration.

ADP and ATP act with enzymes and biomolecules that assist in the respiration process. It’s like a well-orchestrated ballet which the body accomplishes millions of times a day throughout a lifetime.

Each gram of fruit (fuel) is associated with a certain amount of energy. Fats have the greatest amount of energy per gram. Proteins and carbohydrates have about half that of fat. Those carbohydrates such as fiber are not easily absorbed and may have energy per grams of only one or two. Polyols (including the sugar alcohol group) and all organic acids are less than four.

The bioenergetics of respiration

The different energy density of the fuels (proteins, fats, carbohydrates and alcohols) is contingent upon the various proportions of oxidizable carbon atoms. The release of energy from the ATP follows the transfer of electrons from carbon and hydrogen atoms to carbon dioxide gas and water.
The amount of energy actually obtained by the body is lower than the amount present in the fruit; there are losses in the digestive process, the metabolism, and the generation of waste heat.

All chemical processes have varying degrees of efficiency. Theoretically, the energy contained in the mass of one large apple could power all of New York City for a week if a way were discovered to convert 100% of the mass to energy.

The human body is undeniably a remarkable bioenergetic machine. The conversion of mass to energy during a very complex biochemical process is just short of miraculous. It’s something to ponder the next time you take a big bite of your favorite fruit.