In doing research for my book, I came across this article from the June, 1934 issue of Popular Science:
If you eat a diet consisting of 140 grams of fat, twenty-five of protein and fifteen of carbohydrate, you can increase the germ-killing ability of your body, researchers at the Mayo Clinic, Rochester, Minn., have just discovered. Dr. A. E. Osterberg, of the clinic, reported at a meeting of the American Chemical Society that such a diet has been found to increase the production of ketones, or bacteria-destroying acids which are normally manufactured from the fat of the body in the process of digestion.
Interesting that the article calls such a diet ‘balanced’ – perhaps science was smarter then about nutrition than we are now? This is a ketogenic low carb diet the researcher was discussing.
It is also interesting that I have never heard the notion that ketones might act as an internal natural bacterial-fighting mechanism. If that is indeed true, it is another benefit of a low carb diet I was unaware of.
You can check out the article yourself at this link:
Low Carb Confidential 
I think I read somewhere that sugar actually acts as an inflammatory agent in the body and suppresses the immune system. Perhaps by following a HFLC diet, it eliminates much of the inflammation and boosts the body’s natural response to bacteria?