The composition of your body (Lean Body Mass: Fat Mass) is a big component of health from many perspectives. The amount of muscle you carry is vital for multiple processes throughout the body; some we’re only just beginning to recognise. One key function of muscle is to assist the immune system; if you lose your muscle, you lose your body defence system. Consequently the loss of muscle opens up the body to a whole host of maladies from infection through to cancer. This is one reason why the health of a person who has aged typically degenerates into dysfunction and disease as the loss of muscle allows excess oxidative stress and chronic inflammation to pervade the entire body.
In addition to loss of muscle, which alone is devastating, the accretion of excess body-fat is also very damaging. Space only allows me to give one or two examples, so let’s look at the lesser known consequences of being overweight - dementia. A number of population-based longitudinal studies show that midlife overweight (BMI* 25-29), and all obesity (BMI 30 and above), multiplies the risk of dementia.
We know that diabetes, cardiovascular disease, hypertension and metabolic syndrome are all intimately linked to dementia, and high body-fat often co-presents with these dysfunctions. However, there are a small population who do carry extra body-fat but do not immediately display, on the surface, the usual symptomatic alterations in health. But just because the usual markers of disease are not as evident in a small population of overweight individuals, doesn’t mean that there isn’t damage being done silently under the radar.
The now famous Swedish Twin Study showed conclusively, that overweight at midlife increases the risk of Alzheimer’s, and vascular dementia, independent of diabetes and cardiovascular diseases. Simply being overweight (BMI 25-29), without any other apparent health problems, almost triples the risk of later life dementia.
Part of the reason is the chronic inflammation that accompanies excess body-fat; I’ve shown in previous articles how chronic inflammation underlies almost all of the degenerative diseases that plague humanity. But new studies are revealing how overweight and/ or poor diet triggers the degenerative changes in your brain that lead to dementia.
I’ve explained before that our adipose (fat cells) are not simple storehouses of fat, rather more and more we are discovering that it is a neuro-endocrine organ that sends out multiple hormonal signals to the body. One of these hormones is Leptin. Leptin is intimately involved in your metabolism, but either through overweight or poor nutrition and lifestyle it becomes dysfunctional. Being overweight means that you have more fat cells that can secrete leptin, so beyond a certain threshold (18% Body-fat in men and 22% Body-fat in women) it becomes excessive and the system starts to break down. Recent studies have revealed that leptin is vital to regulate beta-amyloid and tau protein both of which are integral components of the changes in the brains of those with Alzheimer’s and Parkinson’s disease. If the leptin system becomes dysfunctional, as it does in overweight individuals, it cannot perform its regulatory role on beta-amyloid and tau, which then allows brain degeneration to continue unabated.
Over at the HPC-UK website there are a few calculators that can give you a bearing on your level of body-fat (once you know this you can use it to reveal your biological age in that regard too). As mentioned above if your body-fat percentage is above 18% (men) or 22% (women) you may want to consider taking steps to bring this down to below these levels.
You can find these calculators here http://www.hpc-uk.net/
*Although BMI has its faults, it is a simple test that is a fair measure of overweight status in a relatively sedentary populace. More active members of society (such as those who train regularly) ideally would use more direct measurements of body-fatness such as skin-folds, bio-electrical impedance or if accessible, the bod-pod or underwater weighing.
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