In one sentence, describe what the following article is about:

A man in a midlife crisis may either gain or lose a lot of weight. With that obviously comes changes in eating and exercising, too. This will seem to come on suddenly instead of a gradual weight loss or gain that most of us experience ten times over. Some men will gain a lot of weight, start binging on junk food and take up a sedentary lifestyle. Others will lose weight, lose interest in food, and even go on crash diets or excessively exercise. In certain cases, both are unhealthy. It's possible that a rogue, gray nose hair set off your man's midlife crisis. If he had this dawning revelation that he's getting old, he may start taking strides to look and stay young, ridiculous as they may be. He may try anti-aging solutions that range from a cabinet full of creams to cosmetic procedures or even plastic surgery. A change of fashion may come, too. All of a sudden it's as if he's raided your son's closet in a desperate attempt to be cool. Sounds terribly embarrassing, but it's nothing compared to plastic surgery. Often men mid-crisis see themselves and realize that they don't recognize their reflection. In their heads, they're still that gregarious 25-year-old with a full head of hair and tanned, glowing skin. One day they wake up and that hair seems to have moved to their nose and ears and that tan, glowing skin is still tan and glowing, just a few inches south. Imagine if you woke up feeling 20 years older. Terrible, huh? That's what your man is going through. He's facing the realization that he's not young anymore and life is half over – and he's weathered to prove it.

Summary:
Pay attention to weight changes. Notice if he obsesses over his appearance. Know that he may look in the mirror and not know who he is.