Aging means a deterioration in the body and an increasing propensity to breakdown and disease. Scientists who study aging are keen to discover the driving force(s) that cause it, but they often seem to be unable to distinguish between aging in itself and poor health, especially when studying human beings. I believe that much of aging is just poor health habits.
Is gaining fat, losing muscle, or developing insulin resistance and diabetes a normal part of aging?
Obviously, virtually all living things age and die. (“Virtually”, because a few living things appear not to age at all.) While aging is a natural process, so infectious and genetic diseases are natural processes too, and we’ve largely discovered how to deal with the first, and are working on the second. There’s no reason that aging can’t be delayed or even abolished; it’s not necessarily inevitable.
Some manifestations of aging are visible, such as grey hair and wrinkled skin, and don’t seem obviously related to lifestyle or health habits, so far as we know. Dysfunction on the cellular level is not visible, but takes place in aging.
Scientists often consider that in humans, aging causes obesity, muscle loss, and diabetes. For example, “Studies have shown that insulin resistance increases with age, independent of changes in total adiposity.” Yet the same study concluded its results by saying, “These results suggest that insulin resistance is more closely associated with abdominal adiposity than with age.”
Similarly, sarcopenia, or loss of muscle, is considered a part of aging. Yet exercise, especially resistance training, and higher dietary protein, robustly fight the loss of muscle, so sarcopenia can’t be entirely due to aging.
Valter Longo, the well-known USC scientist who has studied intermittent and prolonged fasting and their effects on aging, believes that fasting has been shown to have profound effects on aging. Yet, as I pointed out, his studies in humans leave something to be desired, since most of the people in his studies were overweight and/or sedentary. We don’t know how much of the benefits of fasting seen in these people are due to fighting aging or are due simply to better health.
Similarly, domestic lab animals have a tendency to obesity, since they eat highly refined, processed food and are confined to cages. In calorie restriction studies on these animals, much of the benefits to their health may be due merely to preventing them from becoming obese, and not due to a true anti-aging effect.
Scientists consider metformin, the most-prescribed anti-diabetes drug, and rapamycin, an immunosuppressant, to be the best leading candidates for drugs that will actually slow or prevent or even reverse aging. A clinical trial (a trial using humans) of metformin to see its effects on aging is currently underway.
Yet look at who the participants in this trial are: “older adults with impaired glucose tolerance”, that is, these people are pre-diabetic.
We know that type 2 diabetes is caused by, or closely associated with, obesity, dietary sugar and refined carbohydrates, and lack of exercise.
How many of the participants in the metformin clinical trial are obese and/or eat lots of garbage food and don’t exercise? My guess is a very large fraction of them.
Metformin is effective at treating diabetics; it decreases blood sugar and insulin. But if metformin helps the people in the clinical trial, it won’t tell us anything about aging. They’re not healthy, and nothing leads us to think that their ill health is caused by aging rather than bad food, obesity, and lack of exercise.
Metformin may not help people who are lean and healthy and eat good food.
The only way we know if an anti-aging treatment works is if it helps people already healthy.
Some 70% of the American people are overweight or obese, although I’ve argued that the figure is closer to 80% when body fat is taken into account. Excess body fat accelerates aging. So does muscle loss.
The causes of this sad state of affairs are several. One is that people don’t know what to do, and if they go to a doctor to ask, he or she doesn’t know either. “Eat less and move more” is terrible advice. Another reason is that even when they know, most people won’t do much about it. Too hard to give up sugar, much less lift weights.
Whatever the causes, aging isn’t synonymous with obesity, diabetes, and sarcopenia.
Scientists confuse aging with poor health. They overlap but aren’t the same. Until anti-aging treatments extend the lives of healthy animals and humans, we don’t know if they truly work.