Discusses protein cycling in perspective versus the other diseases characteristic of aging emphasizing the importance of weight reduction when indicated.
Mortality and Morbidity
Modern governments for all sorts of mundane reasons now collect and publish data on the health of their populations. Mortality data identifies the causes of death within a population. Here is some selected data from a publication of the United States for the year 200523.
We see in that year that, for those aged 65 to 74, deaths from cardiovascular diseases were over 20 times that from AD and PD. The same for deaths from cancer. Twice as many die of diabetes. Even for those 85 and older, cardiovascular diseases still account for over six times as many as those from the common neurodegenerative diseases. Of course this table is for the primary cause of death and a neurodegenerative disease may underlie something like accidents, suicide, septicemia, inhalation pneumonitis, etc. Nevertheless cancer and cardiovascular disease overwhelm neurodegenerative diseases as a cause of death. Further hypertension, cardiovascular disease and diabetes are themselves correlated with dementia and parkinsonism, the main two reasons for protein cycling in the first place .
In view of this does it make sense to adjust a diet to prevent neurodegenerative diseases when cancer, diabetes and heart disease are much greater threats and are themselves responsive to dietary manipulation? Clearly we would not want a diet that increases cardio, diabetic or cancer risks. Likewise, we would not want a diet that puts reducing minor threats ahead of major threats. If you have the discipline to follow protein cycling indefinitely, you should certainly have the discipline to reduce weight if indicated (or increase it).
There are, however, at least two good reasons why we might want to prevent neurodegenerative diseases before all others: heredity and morbidity.
The death data in the chart is for the entire U.S. population and reflects average risk. Many of us, however, are at much higher risks. Perhaps our ancestors have suffered AD or PD at much higher rates than average. Or more directly perhaps we have tested positive for HD and know we will eventually develop the disease. AD and PD as well as ALS and HD all have familial forms where a particular gene defect has been identified and perhaps we know we have a 50% or greater risk based on heredity and a poor choice of parentage or a 100% risk based on genetic testing..
Morbidity is the measure of the degree to which a disease reduces the quality of life. Its measure is subjective and necessarily less precise than the measure of mortality but can be the more important measure to some. Given the inevitability of death, we might prefer to go with at least our minds intact without the horror of dying a little bit every day for years before the big finale. That is not to say that cancer, diabetes and heart disease are more pleasant though their duration is often shorter; perhaps it is just a matter of personal taste.
Even if our prevention goal is targeted to a neurodegenerative disease, we must consider the affects of our actions on the far more common diseases of aging. Heart disease, diabetes and even cancer rates all increase with obesity. To begin protein cycling while significantly overweight would be ignoring the elephant in the room so to speak. You might say it would be penny wise and pound foolish.
Of course a weight reduction plan could be combined with protein cycling. Calories could be counted and contained and a regular exercise regime followed. Exercise might then be scheduled for when you are on the protein positive half of the cycle when your energy levels are at their highest.
The body mass index (BMI) has been developed as a simple age and sex neutral measure of ideal weight as 19 to 25 kg per square meter of body surface area (skin). Anything above 25 kg is overweight and below 19 underweight. Medical evidence suggests that all adult body weights within this range are reasonably equally healthy. Outside this range, health risks may occur. Above this range, the rates of heart disease, diabetes and cancer all increase dramatically. Of course measuring body surface area is impractical and the area is generally estimated from height. Numerous web sites provide calculators where you can get your individual BMI range. Here is table of just the limit values:
|BMI||19 (low limit)||25 (high limit)||30 (obsese)|
|Height (INCHES)||Weight (LBS)||Weight (LBS)||Weight (LBS)|
The amount of abdominal fat as reflected in waist size has also been identified as a measure of risk apart from BMI from recent studies. Males should have a waist less than 40 inches (37 inches for Asian males) and females should have a waist less than 35 inches (31 inches for Asian females). The ratio of waist to hip should not exceed 0.9 for males or 0.8 for females.
If you have the discipline and need to reduce weight quickly, the alternate day calorie restriction diet (ADCR) may be better suited. It avoids all calories, not just protein calories, in the fasting phase and should induce autophagy as much as or more than the protein cycling diet I am proposing. The protein cycling diet is in fact modeled on the ADCR as a less obtrusive way to achieve the same results. I will discuss it later in its own chapter.
As an example, a 170 lb male adult consuming 2700 calories per day could conserve 8100 calories per week on a ADCR diet if fasting every Monday, Wednesday and Friday and eating normally otherwise. Since there are 3500 calories in a pound of fat, he would expect to lose a little over two pounds a week He could thus rapidly reduce his weight to his ideal BMI range and waist size while getting the benefits of autophagy as well. When he reaches his weight target, he could switch to just restricting protein Monday, Wednesday, and Friday and keep his weight constant.
Aside from weight reduction there is preliminary evidence that calorie restriction and the ADCR diet and, by implication, protein cycling may work against cancer24, asthma and diabetes25as well. In fact much of the current activity in anti-cancer drugs centers on autophagy promoters26. Autophagy induced by protein cycling may even work against some infectious diseases. The tuberculosis bacterium, for instance, hides in an autophagosome within the cell and produces a substance that inhibits lysosomes from merging with the autophagosome and completing autophagy. CR autophagy induction has been shown to override this inhibition and thus promote destruction of the invading bacterium27.
Finally evidence is accumulating that atherosclerosis, the condition underlying most heart disease, is itself benefited by autophagy enhancement; this subject will be discussed in detail later in its own chapter.