One more personal anecdote: I was having problems with somnolence (excessive sleepiness during the day) – even caffeine tablets did not help. These problems got better once I reduced the consumption of milk and dairy (during my Atkins diet in November 2010).
But as I was thinking that ghee (clarified butter) was "pure" fat, that this would be a "safe" milk product, I increased the consumption of ghee. At the same time I ate a lot of beef, which I did think back then to be "good". During that time I got more somnolence again (Again and again and again: Always watch your symptoms and don't change too many things at a time!).
During my "10 days milk&dairy reintroduction" in March I again got more massive problems with somnolence again, which subsided again afterwards.
Now that I had removed beef (in December), reduced caffeine to 3-5 cups of coffee a day (and no tablets!) and finally in April replaced ghee with coconut fat * – both of which should have a roughly similar composition of fatty acids – did my somnolence retreat for good.
A lesson for me: After I found out that milk and
some forms of dairy are
clearly problematic for me, I should have become suspicious of
all forms of dairy
and suspicious of beef (and veal!), even if I did not see any obvious correlation to my remaining health problems.
In extension: If one thing from a nutrition group does cause clear problems (e.g. some cereal grains), better remove
everything from that group (e.g.
all cereal grains,
even gluten-free) from the diet, to see if it helps. And then reintroduce them again to do a challenge.
So after I learned that clearly veal is a problem for me, that beef might be a problem for, I will try to remove all meat from my diet for at least a week and replace it with fish. I already reduced meat somewhat (and am currently on a rather high-carb and high-fat diet! and continue to loose weight, if only slowly) and then tried going vegetarian, but I got a "strange" hunger that made me feel somewhat "jittery", a hunger that subsided only after I ate some meat. I need animal protein, my body makes that much clear. We'll see what fish instead of meat does.
* I initially replace ghee with palm fat, which has an higher content of PUFAs (poly-unsaturated fatty acids). This increased my hunger for carbs, and sometimes gave me a slightly low blood sugar. Only after I switched to coconut oil – with a low content of PUFAs that is comparable to butter/ghee – did my hunger (or rather problem) decrease to a level I would consider "normal" or "adequate".