If, starting today, you began to restrict your caloric intake by 30 to 40 percent, you'd no doubt get awfully thin, but you'd probably live longer. Of course, that kind of deprivation might make you rethink your reasons for wanting to live longer, but regardless, it should work. At least it has on chimps, dogs, rats, worms, flies, and yeast.
It likely has to do with things like increases in SIRT 1 activity, telomere length, and mitochondrial health, among other things.
So this food-restricted, skinny-ass plan to live to 100 or beyond should work fine, assuming you don't have to undergo any major surgeries. If you do, however, you're probably screwed, because a PhD student in Rotterdam found out that the more muscle you have, the more likely you are to survive a major surgery (and by inference, a major illness).
Jeroen van Vugt looked at 206 people with an aggressive type of colon cancer. All of them had undergone surgery and 44% of them lost enough weight to be diagnosed with sarcopenia, a degenerative loss of muscle mass.
Patients in this group were more prone to surgical complications and had additional surgeries 2.1 times more often than patients with a healthy amount of muscle mass.
Enthused by what he had discovered, van Vugt then followed another group of 816 colorectal cancer patients from whom doctors had removed affected organs. Rather than just look at muscle mass, van Vugt went one step further – he determined both the muscle mass and the muscle density of each patient.
Let's look at that term, muscle density, for a minute. Say you have a certain amount of muscle mass, but because of bad diet and lack of activity, your muscle fibers shrink and your body fat increases. Your muscles may look as large, but they're definitely not as hard (or strong) as the muscles of an active person.
What van Vugt found was that people with more muscle mass maybe died a little less frequently than people with little muscle mass, but it wasn't statistically significant. However, people with more muscular density definitely died less frequently than those with low muscle density.
Van Vugt also looked at people who'd had a liver transplant. Again, those with a higher level of muscle mass had better survival rates.
Van Vugt summarized his findings this way:
"Low skeletal mass is associated with increased age and disease, such as cancer and liver disease. Considering the increasing age of the population, the increasing incidence of cancer, the remaining shortage of donor livers, and the increased surgical and medical treatment options, skeletal mass could be an important addition used for risk assessment. Moreover, it may be a therapeutic target to improve treatment outcomes."
While van Vugt focused solely on surgical interventions and not illness in general, it's not a huge stretch to assume that additional muscle mass or muscle density might be useful to help a body weather long-term illnesses, too.
So, if you want to live a good long time, you have some things to take into consideration. If you plan on never needing surgery or getting sick, don't care about looking good for the ladies, don't mind not having the physical strength to open a bag of low-calorie seaweed (or whatever tasteless thing you've resigned yourself to eating), and don't mind having a maddening, gnawing hunger torturing you every waking minute, go the calorie-deprivation route.
If, however, you do care about any of the aforementioned things and you have the realistic view that you might some day get sick or need surgery for some major illness, go the muscle-building route.
Of course, if you're reading this site, you're likely already doing that. Consider this study an affirmation of your lifestyle choice. You may also want to use this study to convince your parents to get themselves to the gym, assuming you want them to live longer.
- van Vugt JLA. The impact of low skeletal muscle mass in abdominal surgery. Erasmus University Rotterdam. 2017, December 20.