Rear-guard defenders of the food pyramid and conventional nutrition have always claimed that the only thing that matters about diet is the caloric intake, and that protein/carb ratio is irrelevant. Now there's been a scientific study that proves them wrong.

"A lot of our assumptions about a calorie is a calorie are being challenged," said Marlene Schwartz of Yale. "As scientists, we need to be open-minded."

Others, though, found the data hard to swallow.

"It doesn't make sense, does it?" said Barbara Rolls of Pennsylvania State University. "It violates the laws of thermodynamics. No one has ever found any miraculous metabolic effects."

Well, sorry, Barbara, apparently someone just did.

It doesn't violate laws of thermodynamics at all. It only violates the conventional wisdom of folks like you, whose nostrums have been keeping people unhealthy for decades.

If only food scientists would think like chemists and biochemists. Then the realization would dawn that calories determined using a bomb calorimeter are not used by the human body by combustion. The human body uses many different chemical reactions to digest food, which results in food calories being absorbed differently depending on the type of food.

Are we also to assume that different calories are assimilated in the same manner?

Perhaps some calories like protein calories reqire more 'energy' to assimilate.

Also, is it not possible some types are more easily excreted?

This means that Barry Sears of "The Zone Diet" fame also got it right. Maybe even more so than Atkins. If you want to understand how carbs and protein are handled differently by our bodies go read his book. He explains it well.

In a nutshell it comes down to this. Protein stimulates the production of the hormone glucagon while carbos stimulate the hormone insulin. For the bodies primary source of energy, high glucagon relative to insulin tells the body to burn fat. High insulin relative to glucagon tells the body to burn carbohydrates and then store whatever is left over as fat.

The Zone Diet is about controlling insulin levels. High insulin is the culprit for everything from storing the extra weight, to high cholesterol (insulin stimulates the production of cholesterol in the liver), to thickening and clotting of the blood, to suppressing the bodies natural production of human growth hormone (HGH), and more.

Dr. Sears realized that the secret to not just weight loss, but good health in general, is preventing the overproduction of insulin. And the only way to do this is with diet.

There's also the matter of genetics. As I understand it, most of Europe used milk of cows and goats for millenia while most parts of China have not. So I would anticipate that there would be a difference in how well someone could digest milk based on their ancestry. In a similar fashion, I suspect that people vary greatly in how much starch and other carbohydrates they can consume relative to protein. That would in part be due to what foods their ancestors normally ate.

Since trying out Atkins I must admit I have been shocked at just how intolerant my body is towards wheat products. I've felt much better since I kicked bread and pasta off the diet.

I wish a few of these dietician's poo-pooing low-carb diets would actually try one, rather than just say "perhaps the people eating more calories also got more exercise or they were less apt to cheat because they were less hungry." Why don't they just try it, and find out? I remember when I went on Atkins - I ate a LOT more food than I was when I wasn't dieting. I had to eat more often too, because I'd get so hungry. I still lost weight though, because instead of grabbing a pint of Ben and Jerry's when I wanted a snack, I'd do stuff like eat hard-boiled eggs. I lost 20 lbs. (More than I should have, actually, had to add carbs back in to get to normal weight.)

Egad. Whatever you might think of the Atkins diet (or Zone), I find it hard to see how this study provides any useful information, let alone proves anything. For example:

* What kind of weight was lost? You can lose 20 pounds by lopping off a leg, but that's not very desirable from a health standpoint. Did these people lose fat? Was there any difference in fat loss between the groups? Did anyone even test for that?

* Did any of these people exercise? That makes a big difference in how the body metabolizes nutrients.

* What kinds of carbohydrates did the high-carb group eat? Since they ate in an Italian restaurant, I assume it was mostly pasta, but it could have bowls full of Jell-o for all we know.

* The low-carb group ate 5% carbohydrate, 15% protein, and 65% fat. What was the other 15%? Did they eat the napkins?

Most importantly, this study was on a sample size of 21 people, divided into three groups. There is so much metabolic variation between individuals that there's no way to conclude anything from groups that small. The first four questions might be answered in the study itself, but with seven-person groups we still can't conclude anything meaningful.

Its interesting to me that the nutritianists know that Americans (as a group) have been getting fatter for decades now, but cannot consider the chance that the food pyramid they've been pushing for decades now, might have something to do with it.

The BBC did a show comparing over 9months, Weight Watchers, Atkins and Slim Fast.

Basically they concluded that the Atkins people lost most quickly but many lapsed, however, the reason many of them lost is they were, in fact, ingesting a lot less calories than they were pre-Atkins.

I eat a lot less crap when I restrict my carb intake, which includes cutting out beer.

At the risk of raining on everyone's parade, I'll throw my two cents worth in and suggest that all the bilge that is regurgitated by the frequently opposite fad diet ascribers could very easily point to a psychosomatic factor in weight loss. How's that for mind over matter?

Dave, your last sentence bummed me out. What booze doesn't contain carbs besides wine?

What makes you think that wine doesn't have carbs? Alcohol itself is a carbohydrate.

If it grows (i.e. as a plant), it's a carbohydrate. But wait, there's more...

Remember, according to Barry Sears, the secret is to keep insulin levels from going too high. The body maintains a normal blood sugar level by increasing insulin when the sugar levels rise. However, when responding to a rapid rise in blood sugar, most of us tend to produce more insulin than necessary and this overreaction results in high insulin levels.

Here's the key: Different forms of carbohydrates enter the blood stream at different rates. For example, potatoes, rice, grains, corn, and bananas enter the blood very quickly. As such, these tend to adversely affect insulin levels because they cause the blood sugar level to rise sharply. One can eat these, but it should be only in very small portions. On the other hand, foods like apples, cantaloupes, lettuce, enter the blood stream slowly. As such, the insulin levels are more easily maintained.

Fiber and fat, preferably the mono-unsaturated kind, is helpful in slowing down the rate at which the carbos enter the blood stream. Sources of "good" fat are almonds, avocados, olive oil, peanuts, and macadamia nuts.

Do you see the irony here? Carbos are the culprit and fat actually *helps* reduce the affects of undesirable carbos. That is why, when America became fat phobic, Americans became fatter! It takes fat to burn fat! That's because by keeping the levels of carbo-stimulated insulin close to the protein-stimulated glucagon our bodies are put into a fat, not carbo, burning mode.

With the Zone Diet, you combine protein, carbohydrates and fat (in a recommended ratio), *every* time you eat. With this approach you burn fat, not lean muscle (as can be the case with Atkins).

I'd assumed it had more to do with grains than plants. Nearly every alchohal except wine comes from a grain of some type. So basically booze is a problem with the no carb diet.

I've been convinced for years that all pro-food pyramid nutritionists must have flunked both basic algebra AND junior high school biology.

Why? Well, nothing you eat is usable as raw energy by cells until it's turned into ATP. The only thing that get's turned into ATP is glucose.

Glucose requires almost no energy to turn it into ATP. Sucrose and other simple sugars require more energy to turn them into glucose, and hence ATP.

More complex carbs require yet more steps, and hence energy, to get broken down into simple sugars, then glucose, and then ATP.

Proteins and fats require even more energy to release what calories they provide.

Hence, calories derived from a given food is given by:

Usable Calories = N times Input Calories

where N is a smaller and smaller fraction the farther you are from ATP.

Hence, you get much more glucose with a larger N (almost one for glucose itself, and close to it for sucrose), and therefore up your odds of an insulin spike and having excess glucose stored as fat.

Ergo, the larger the proportion of your diet that is carbs, the more weight you'll put on.

After having this epiphany from first principles while suffering a week of pain after getting braces at age 16, I lost over 50 pounds gradually over 9 months by cutting all processed sugar from my diet, and lowering the proportion of other carbs.

Christ, and they call some of these food people SCIENTISTS!!!!

Alcohol itself is a carbohydrate.

Some booze is lower carb than other, at least according to the charts Atkins produces. Beer is by far and away the worst at 17g a pint, that's also around 190 calories. Red wine is next worse and then Dry White Wine, under 1g a glass.

Vodaka is pretty much ok. 0g per shot. So Vodka with low-cal tonic is actually ok. (Perry De Havilland of Samizdata has, I read, been happy to switch to Low-Cal Gin and Tonics. He's lost 20lb's or something over the last year)

Key to the Atkins thinking is alcohol should not, in moderation spike the insulin level too much. Drink too much, however, and you will end up with alcohol induced hypoglyceamia. Not ideal for dieting.

Wow, I knew Perry had lost a bit, I wonder how much of the 20lbs is due to the low cal tonic? :-)

One other thing I don't understand about the standard way people think about calories-- it doesn't account for the fact that NOT ALL CALORIES ARE USED AS CALORIES!!! Geez, where does everyone think their bones, skin, and muscle come from? Muscle is made out of protein, cell walls use fat in their makeup. So the whole calorie is a calorie thing was brain dead to begin with.