Carrying more visceral fat in your body than you need to get by - the standard result of a life involving too many calories and too little exercise - reduces your longevity. It also greatly increases the chances of your later years being unhealthy, painful and expensive. I've looked at a range of mechanisms by which this happens:
- A Gentle Reminder That Fat Will Eat Your Mind
- Fat and Inflammation
- How Excess Fat Tissue Slowly Destroys You
- Fat, Inflammation and Atherosclerosis
Knowing is half the battle, but putting the work in to shed that fat will pay great dividends over the years. Who wants to be frail and incapacited by diabetes and Alzheimer's at 70, versus fit enough to get out and play a game of tennis whenever you feel like it?
Continuing this examination of reasons not to be overweight, I noticed an interesting paper that demonstrates quite directly the cost of visceral fat (visceral adipose tissue in science-speak) on life span.
Caloric restriction (CR) can delay many age-related diseases and extend lifespan, while an increase in adiposity is associated with enhanced disease risk and accelerated aging. Among the various fat depots, the accrual of visceral fat (VF) is a common feature of aging, and has been shown to be the most detrimental on metabolic syndrome of aging in humans.
We have previously demonstrated that surgical removal of visceral fat (VF) in rats improves insulin action, thus, we set out to determine if VF removal affects longevity.
We prospectively studied lifespan in 3 groups of rats: ad libitum fed (AL), 40% caloric restriction (CR) and a group of ad libitum fed rats with selective removal of VF at 5 months of age (VF-). We demonstrate that compared to AL, VF- rats had a significant increase in mean and maximum lifespan and significant reduction in the incidence of severe renal disease.
CR animals demonstrated the greatest mean and maximum lifespan the lowest hazard rate of death as compared to AL rats. Taken together, these observations provide the most direct evidence to date that a reduction in fat mass, and specifically VF, may be one of the possible underlying mechanisms of the anti-aging effect of CR.
This conclusion seems likely - but note that sensibly practicing calorie restriction does much more under the hood than just lower the level of fat in your body. Also note that you don't need to be full-on calorie restricted to lose enough visceral fat to greatly benefit from its absence. The difference between an average, healthy body weight and what passes for the norm in much of the developed world today is large enough to make a big difference to health and longevity in later life.
The body is a complex machine, and like all machines, it ages more slowly if you take better care of it. That much should be common sense.