Is Food My Friend or My Enemy?

"What doesn't kill you makes you stronger." —Neitzsche

We have evolved a complicated relationship with eating that is the reverse of Nietzsche's well-known aphorism: Food makes you stronger—and then kills you.

Here’s a truly profound and obvious statement: The more days that you have been alive, the more likely you are to die. Why? What do you do every day that leads inexorably to your death? Eating.

Eating provides your body with the energy stored within the carbon bonds that are contained within the fats, carbohydrates, and proteins that make up your diet. Breathing brings oxygen to your mitochondria to carry away the carbon debris that forms when these bonds are broken apart. This single critical activity, called oxidative metabolism or respiration, is absolutely essential for your daily survival—and is also the most important factor that very slowly, minute-by-minute and day-by-day, ages you until you die.

In addition to oxygen, the air you inhale contains 73 percent nitrogen. During respiration, nitrogen and oxygen are converted into highly reactive molecules that initiate a series of biochemical changes that lead to your death. (For a video explanation, see my TED Talk here.)

The generation of reactive oxygen and nitrogen species is an inevitable consequence of life. Ordinarily, the formation and degradation of reactive oxygen and nitrogen species are regulated by cellular defense systems that include a group of scavenging enzymes able to remove oxidants or their precursors. In addition, non-enzymatic antioxidants such as Vitamins E and C delay or prevent the production of reactive species. Repair and removal systems complete the damage defense.

However, even if these preventive and repair systems are working efficiently, they cannot fully prevent oxidative damage. This imbalance between the excessive production of reactive species and the body’s ability to detoxify them or repair the resulting damage is termed “oxidative stress.”

Oxidative stress directly damages cellular proteins throughout the body. The protein damage is recognized as a significant pathophysiological event leading to disease and aging. Damaged proteins predispose humans to numerous age-associated diseases, including (but not limited to) Alzheimer’s disease, alcoholic liver disease, coronary artery disease, chronic obstructive pulmonary disease, non-alcoholic fatty liver disease, mild cognitive impairment, metabolic syndrome, Parkinson’s disease, rheumatoid arthritis and Type 2 diabetes, lethal prostate cancer, sickle-cell disease, sepsis, psoriasis, interstitial lung disease, multiple sclerosis, renal failure, autism spectrum disorder, diabetic complications, and oral squamous cell carcinoma. The critical role of these toxic byproducts of protein oxidation and nitration is so well understood that they are now being used as biomarkers of disease status in clinical settings.

Mitochondria are the primary generators of age-enhancing oxidative and nitrative byproducts. Smoking, obesity, excessive caloric intake associated with extreme exercising, heavy metal exposure, pollution and excessive alcohol consumption also contribute to the augmented formation of reactive oxygen and nitrogen byproducts that accelerate multiple aging processes.

Being a male further complicates the impact of eating. Testosterone increases the energy expenditure from muscle mitochondria leading to an increase in the number of mitochondria within each muscle and an increase in the production of ATP. Much of the energy used for the increased production of ATP is drawn from the body’s stored fat. So far, this all sounds great.

Unfortunately, the testosterone-driven mechanisms that control the metabolism of fat for energy have significant consequences for males. Testosterone alters how males metabolize food and increases the amount of heat their muscles produce during normal respiration. Testosterone, due to its effects on a specialized protein, called Uncoupling Protein or Thermogenin, makes the normal food-to-energy conversion process in mitochondria become inefficient—that is, cells waste more energy as heat, making men feel warm. Typically lacking in both testosterone and significant muscle mass (though not always), women tend to produce less body heat from their food; consequently, it is usually much harder for women to lose weight than it is for men.

The male body, particularly its muscles, can waste a considerable number of consumed calories as body heat. Males, to the chagrin of many females, can lose weight by simply sitting still. In contrast, women, who lack the mitochondrial uncoupling actions of testosterone, usually have to lose weight the old-fashioned way, by not consuming as many calories.

Unfortunately, for males, wasting calories to produce heat has some negative long-term consequences. First, males tend to need more calories per day than do females; consequently, males generate more harmful reactive oxygen-free radicals (ROS). These ROS are harmful to the body and negatively affect men’s health and reduce their longevity, as compared to women.

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That’s why we are constantly being reminded to consume fewer calories every day (the only scientifically valid way to slow the aging process), eat antioxidant-rich fruits and vegetables (to defend your body from the consequences of breathing), stop smoking, and reduce exposure to pollutants (both produce oxidative stress and inflammation) to live a healthier life. However, even if you do all these things, you will not live forever, because we are drawn to food like a moth to the flame.