There is a fad that's been circulating around the Internets for years now, and I'm sure is even older than that: the idea of so-called "negative calorie foods". The basic premise is that some foods require more calories to digest than they actually provide. For instance, a food that provides 5 calories, but requires 10 calories worth of energy for your body to process it, is considered to have negative calories.
It's an interesting concept, and it would be awesome if it were true. Unfortunately, I have been unable to find any concrete proof either way. We know how to determine a food's caloric content, but I wonder if we know how to determine how much energy it takes to process it? In trying to find answers online, I found several people who claimed to be knowledgeable, but who were obvious idiots, and/or didn't bother checking their facts. For instance, on this page, I found this comment:
"Celery has almost zero calories, it's so minuscule we round down to 0."
I've never heard of anyone making this claim. If we consult the USDA Standard Reference, we discover that an 8-inch stalk of celery contains about 6 calories. This is not a miniscule amount (unless compared to a Big Mac), and I certainly wouldn't round it down to 0.
I found several other references to celery containing anywhere from 5 to 20 calories per serving (though the serving size was never stated), and guesses that eating a single serving would burn anywhere from 5 to 20 calories. Even Snopes, which I lose more and more faith in every time I read anything there, claims the "negative calorie" concept is true, but offers absolutely no evidence or proof.
Can anyone tell me definitively how many calories are burned by eating a single serving (say, 40g, the approximate weight of an 8-inch stalk) of celery? I want a number, and I want to know how that number was obtained.
My next complaint involves cooking alcohol out of food. There are plenty of people that will tell you, "don't worry, the alcohol burns out". In my experience, these are people that either think you're silly for caring, or are reassuring themselves because they want it to be true. Other people will tell you that you can never burn it all out. The most outspoken of these that I've heard is Alton Brown, followed by his good buddy Ted Allen.
Both Alton and Ted have discussed this on their shows, Good Eats and Food Detectives, respectively. Food Detectives is kind of a culinary Myth Busters, but is far more scripted. They frequently perform experiments to prove or disprove myths, but in the case of the alcohol, they did a food demo that proved nothing, and then stated their "fact" as gospel.
Alton Brown has stated repeatedly that alcohol never cooks out completely, but has never offered proof. Some years ago I did some research and found a report on the USDA's website that seemed to imply that after 2 1/2 hours of oven roasting, the level of alcohol left in foods is 0% (which I'm guessing is actually < 0.5%). Unfortunately, in more recent visits, this report seems to have been removed. I have been unable to find it for years.
So, it begs the question: does alcohol really cook out, or not? Does anyone have any proof? Or can anyone at least point me to a report or study somewhere that even suggests something either way?
I'm not convinced on the negative calorie thing, or the alcohol thing. And I'm sick of people making claims with nothing to back them up. I want proof.