The young begin with robust vitality and resiliency. They ride high on the torrent of growth and sex hormones coursing through their vessels. Their digestive capacity rivals a garbage disposal, the immune system is well armed and alert, and any injury is repaired with remarkable speed.
 
This trove of healing riches and seeming invulnerability invites a lot of squandering and abuse.
 
That's because youth health is a dangerous illusion. A young body is incredibly adaptable. But that doesn't mean it's invincible.
 
Wrong living in youth is like writing checks against a health account. Health potential is deposited at conception and is never added to. Every violation of healthy living draws down from the original the balance.
 
It all begins with infants sucking on a latex nipple on the other end of which is the granddaddy of all junk foods—baby formula. Then there is weaning to a smorgasbord of nutrient-impoverished processed foods cloyed with sugars and starches, decorated with every manner of additive to make food 'fun,' and lubricated with hydrogenated oils to create just the right "mouth feel."
 
Kids drink oceans of soda, eat herds of burgers, vats of breaded and deep-fried whatever, and enough pizza dough to stretch to the moon and back. Once puberty kicks in, they keep ungodly hours and exercise little other than tapping keyboard buttons. In general, they are totally oblivious to health and healthy living. 

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​Nevertheless, deductions from their health account silently continue.¹
 
Despite all this dietary and lifestyle abuse, kids apparently remain healthy. Not just a little, but a lot. They have tons of energy, sleep like logs, can excel in school, and win state sports championships.
 
What's the deal? Adults can't live like that. We'd get sick or kill ourselves trying to keep pace with their antics.
 
Youth seems to excuse a lot and mask the damage.
 
But all is not well. Autopsies of young Korean and Vietnam War casualties revealed an extremely high incidence of atherosclerosis, the underlying pathology of heart attacks. Yet there were no detectable symptoms of heart disease in these soldiers as they went through rigorous basic training and fought in demanding wars. Problems lurked hidden within, growing like a slow cancer. If these soldiers had lived, their wrong choices would have eventually manifested in middle or later years as heart disease or a heart attack.²
 
A 1999 study of autopsies performed on almost 3000 men and women between the ages of 15 and 34 showed the same results. Atherosclerotic lesions (the plaques that plug vessels and cause heart attacks and strokes) in the aortas and most of the right coronary arteries (feeding the heart muscle itself) were observed in the youngest age groups and increased in prevalence with age.³ As a result of such findings, the American Heart Association released its recommendation that everyone over the age of 20 should be checked routinely for signs of potential heart trouble. (That, however, is not a solution. It's too little, too late.)

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​Heart disease is, by and large, a lifestyle and nutritional disease. (No, it's not from butter or cholesterol.⁴) So too are most other chronic, degenerative, adult-onset diseases such as cancer, diabetes, obesity, autoimmunity, arthritis, dental deterioration, obesity, and more.
 
Their root cause is the shift from ancestral dietary and lifestyle patterns--what we are genetically programmed for-- to inactivity and a glut of refined carbohydrates and contaminated nutrient-stripped processed foods.
 
It's a cruel irony that the carefree lifestyle we enjoy while young will create such havoc and suffering in our adult years. We assume that if we felt well and were healthy lollygagging around the house eating junk food as kids, that as adults we should be able to continue that way indefinitely.
 
But youth is not a free pass. The damage keeps adding up.
 
Too often, adults blame their poor health on bad luck, aging, or genetics. They offload responsibility to a doctor and get started on a panoply of pills that eventually escalates their problems.
Genuine health demands reflection—an honest look at history and how choices made over time shape the body’s health trajectory.
 
So, all is not well just because a child "seems fine" on Mountain Dew, Ding Dongs, and Cocoa Puffs. One of the greatest gifts parents can give kids is intelligent health guidance. Children have no idea what's going on; they think nutrition is cotton candy and Kool-Aid, and life is the next screen to scroll. Their robust and forgiving bodies should not fool us. 

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​It’s easy to confuse love with indulgence. But real love is not about saying yes to whatever kids want. It’s not about convenience, like handing over a phone and a bag of snacks to keep them quiet. True care is helping them avoid a life of chronic illness caused by choices they’re too young to understand.
Our job as parents is to save them from themselves and the seductive modern world. We can do that by reconnecting their minds and bodies with their genetic roots, as discussed in this previous Quora post.
 
In a nutshell, rearing kids is about hypocrisy. Teaching them not to do what we probably did.
 
References:
 

1. Cordain, L., et al. Origins and evolution of the western diet: Health implications for the 21st century. American Journal of Clinical Nutrition, 81 (2005), 341-54.
2. Search PDAY Research Group--Pathobiological Determinants of Atherosclerosis in Youth
3. Strong, J. P., et al. Prevalence and extent of atherosclerosis in adolescents and young adults. Journal of the American Medical Association, 281 (1999), 727-735.
4. Wysong, R. L. Lipid nutrition: Understanding fats and oils in health and disease. Midland: Inquiry Press, 1990.