Fight Aging!

In the interests of informing those new to membership in the human race, I should note that excess visceral body fat is bad for your long term health. In addition, lack of exercise has many of the same end consequences. The trifecta of diet, exercise, and levels of fat combine to exert a great influence over the future trajectory of your life - including such items as your risk of diabetes, risk of dementia, and your life expectancy.

All a long way of saying if you get fat and stay fat, your biochemistry is more likely to destroy the structure and function of your mind. And those thinner old people who are suffering as well? Their developing dementia - partially caused by earlier excess fat - led them to lose weight during their decline. There are easier ways through life than this, and unlike many of the slings and arrows we suffer, for the vast majority of us our level of body fat is a choice.

...

Exercise reduce the rate at which some of the cellular and biomolecular damage of aging accumulates, either by slowing the ongoing addition of new damage, or by modifying the processes of repair. In a future of rapidly advancing biotechnology, even a single additional year of time to wait for new therapies is a big deal.

For the sake of piling it on, here's another study on fat, exercise, and insulin resistance - one of the precursors to type 2 diabetes, and an issue prevelant amongst older people.

Physical Inactivity and Obesity Underlie the Insulin Resistance of Aging:

Age-associated insulin resistance may underlie the higher prevalence of type 2 diabetes in older adults. We examined a corollary hypothesis that obesity and level of chronic physical inactivity are the true causes for this ostensible effect of aging on insulin resistance.

...

We compared insulin sensitivity in seven younger endurance-trained athletes (YA), 12 older athletes (OA), 11 younger normal weight (YN), 10 older normal weight (ON), 15 younger obese (YO) and 15 older obese (OO) subjects using a glucose clamp. The non-athletes were sedentary.

...

Insulin sensitivity was not different in YA vs. OA, in YN vs. ON or in YO vs. OO. Regardless of age, athletes were more insulin sensitive than normal weight sedentary subjects, who in turn were more insulin sensitive than obese subjects. Conclusions: Insulin resistance may not be characteristic of aging, but rather associated with obesity and physical inactivity.

A small sample size, I know, but it's representative of many other similar studies. Some of what we see as characteristic of aging these days is in fact characteristic of the effects of excess fat, too much food, and a lack of exercise. You can't turn back the clock just by taking better care of yourself, but you can choose to make a significant difference as to how fast you are damaging yourself - and thus your risk of suffering all of the common age-related conditions.