Aging Part 2: Caloric restriction

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Caloric restriction, or the generalised decrease in energy obtained from your daily food intake, has been the only scientifically-backed mechanism to date, which can positively augment the aging process.

Although no studies have been performed tracking humans over the complete entirety of their lives, and comparing their maximal lifespan to the average amount of food they consumed, evidence from a myriad of animal studies appears convincing of several health benefits obtained from caloric restriction.

How could decreasing your daily calories as a whole be beneficial though?

If we think back to last week’s article regarding the mitochondrial theory of aging, we see that increased metabolism in GENERAL causes cummulative cell damage. This damage is repairable to an extent while we’re young, but the repair capacity decreases significantly with age. Thus in a way, it is the metabolism keeping you alive, which is inherently aging you all the time.

By giving your body less fuel substrate to constantly burn up (producing toxic by-products in the process), it can remain functioning optimally for longer. There is decreased cellular damage via increased activation of repair mechanisms. Evolutionarily, it would make sense that famine or times of low food avaialbility upregulate our built-in repair and protection mechanisms. This would ensure we remain fit for reproduction when the environmental stress passes.

Prolonged high levels of blood glucose also exhibit extremely detrimental effects on your heart and blood vessels. It is not necessary to be diabetic to have blood sugar high enough to cause such damage, and simply eating a little more than you ‘should’ over many years, can greatly increase the risk for cardiovascular disease, stroke, or heart attack. Other markers of disease also tend to be decreased, as can be seen in the table below

In addition, such caloric restriction has been shown to benefit certain cognitive functions, like improving memory. The decreased availability of calories also signals the body to perform more ‘recycling’ of its proteins. Problems with this recylcing mechanism have been implicated in MANY neurodegenerative diseases, like Alzheimer’s and Parkinson’s disease.

Table summarising some of the changes occurring with CR. Increases in HDL cholesterol, together with low LDL concentrations, are good indicators for cardiovascular health

Table summarising some of the changes occurring with CR. Increases in HDL cholesterol, together with low LDL concentrations, are good indicators for cardiovascular health

All this being said, a fine balance must be struck between taking in enough calories (and from good sources), while still maintaining the TOTAL intake at a relatively low level. As a criteria for “restriction”, simply try and reduce your energy intake by 10-15%. If you feel tired and lethargic, reverse the change immediately.

As I’m not a dietician, I cannot stipulate exact eating plans, but as a physiologist I know that caloric restriction on the whole is highly beneficial. It seems that Nature would rather have us on the fringe of hunger, than to be well-fed and glutinous.

The take home message, is to reduce your food intake as much as your lifestyle allows. Just because you have a psychological “craving” for something, doesn’t mean your body needs it. Think about it: the incredible enjoyment and euphoria you experience while the chocolate is in your mouth passes after 5-10 seconds. However, your body’s work is just beginning as soon as you’ve swallowed, and it can take our bodies days to weeks to process this nutrient influx, long-after we’ve forgotten about it in the first place! Knowing that such a simple change in lifestyle can do so much for you in the long-run, does it not make sense to eat just a little bit less. We simply do not need all the energy we’re taking in with our modern, Westernised diets and corresponding lifestyles!

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