Evolution and Middle Age

Evolution has given humans a huge advantage over most other animals: middle age. The article is total hogwash, an example of evolutionary thinking at its worst. For instance:

An important clue that middle age isn’t just the start of a downward spiral is that it does not bear the hallmarks of general, passive decline. Most body systems deteriorate very little during this stage of life. Those that do, deteriorate in ways that are very distinctive, are rarely seen in other species and are often abrupt.

For example, our ability to focus on nearby objects declines in a predictable way: Farsightedness is rare at 35 but universal at 50. Skin elasticity also decreases reliably and often surprisingly abruptly in early middle age. Patterns of fat deposition change in predictable, stereotyped ways. Other systems, notably cognition, barely change.

Each of these changes can be explained in evolutionary terms. In general, it makes sense to invest in the repair and maintenance only of body systems that deliver an immediate fitness benefit — that is, those that help to propagate your genes. As people get older, they no longer need spectacular visual acuity or mate-attracting, unblemished skin. Yet they do need their brains, and that is why we still invest heavily in them during middle age.

So, our eyes begin to go bad because our body cannot afford to invest any of its resources in it? This would require showing that our resources are so limited that the body cannot afford to repair eyesight. Nonsense. Calorie restriction and intermittent fasting cause greater repair of cellular and organ systems than in the fully fed state, which clearly shows that repair is not limited by resources, but is a controlled process.


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