I read the book Good Calories, Bad Calories by Gary Taubes. It's a review of nutritional science by a smart and careful nonscientist that says the conventional dietary advice of the last 40 years is totally wrong. The gist is that the human body is not evolved to handle refined sugar and starch, and if you eat a lot of it your metabolism goes haywire and starts laying down fat, and causing additional problems unrelated to fatness. A corollary is that saturated fat and dietary cholesterol aren't bad for you. The obvious conclusion is that reduced-calorie, high-carb, low-fat diets are not only unpleasant, they don't work. If you want to limit something, it should be sugar and carbs, and even people in studies who were allowed to eat all the meat they wanted (but nothing else) lost weight.
It was a pretty compelling read. I was an on-and-off vegetarian for several years on ethical grounds, but I was assuming (based on all dietary advice except the Atkins Diet) that vegetarianism was at least harmless and possibly much healthier. Well, I've had to put that assumption in the trash can. Not that Taubes's book is perfect. I didn't think he addressed the question of why the human body evolved to be not just indifferent to, but intolerant of, simple carbs, nor did he address evidence against, like certain tribes that live on carbs but don't get fat. (Authors have to be very careful about touching that sort of thing because it implies a group can genetically adapt to the available diet in only a few thousand years, which implies that race has biological significance...) But taken as a whole, sugar seems to be really bad for you, and if you cut down on sugar or carbs, you pretty much have to eat more meat. This was actually standard advice up to about 1970, as funny as that sounds today.
Eating too many carbs screws up the natural insulin response to elevated blood sugar. I got curious as to how responsive my blood sugar is to my diet. So I got a blood sugar meter and took three days of baseline readings on my normal diet. These are taken first thing in the morning on an empty stomach. The meter was cheap and easy to use, and the lancets are so tiny you hardly feel them. Here's what I got:
100, 113, 110 mg/dl
Anything over 99 is considered pre-diabetic! (That is, it indicates you might be becoming insulin-resistant, which is Type 2 diabetes. More than 126 is diabetic.) Now, I did eat about three pints of ice cream over those three days, which I don't do every weekend, but I probably do it once a month. We scientists must be brutally honest. I'm maybe 10 pounds overweight but generally healthy.
Then I started an experimental diet cutting out sugar and carbs as much as I could. I went to the grocery store and bought a bunch of meat, cheese and eggs. I even bought Slim Jims to snack on instead of chips or pretzels. I got only green leafy vegetables, not potatoes or anything starchy like that. This would not be sustainable as a permanent diet - it's just a temporary experiment to see what would happen.
On this experimental diet my sugar consumption dropped from about 150 grams/day to near zero, and my total carbs decreased from 400 grams/day to about 100.
After one day of this sugar-free diet, my glucose dropped to 75 mg/dl!
I got all excited and figured that with two more days of low readings, I could prove that my glucose is strongly and rapidly influenced by my diet, and call off the experiment to return to a more moderate (but still reduced-sugar) diet. Well...
On Day 2, my glucose bounced back to 115 mg/dl. This was a surprise. I can only conjecture that on the morning of Day 1, I took an omeprazole tablet (that I use for longstanding acid reflux) and it delayed my digestion such that I didn't get a fasting glucose value on Day 2 but something more like a post-prandial value. (Post-prandial is the term doctors use for "after eating" when they don't want you to know what they're talking about.) I also got a mean headache on the evening of Day 2, but it went away and I started feeling pretty good.
So it's going to take several more days to see what the real trend is. The human body is a strange machine and nothing is clean and simple. My plan is to take a reading every hour some day, to see how it goes up and down. I'd like to do this on one day when I take the omeprazole and on one day when I don't, for comparison. But I only have 5 more lancets left and I'll have to find a place where I can buy more. Stay tuned!