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Showing posts with label Sugar. Show all posts
Showing posts with label Sugar. Show all posts

Wednesday, July 09, 2008

Good Calories Bad Calories - Bad Science




If you thought I only blogged books I like, here's the exception. Good Calories Bad Calories is NOT a well written book. Its selectively researched, poorly organized, badly written and not much fun to read. So why bother? Some of the ideas are too important to ignore. Others too important to NOT be challenged.

If weight gain isn't America's number one health problem, it's headed there in a hurry. And it looks like there is no way to stop it. But we might slow it down if we get the right information.

So, ARE some calories better than others? Is this the magic answer? I doubt it. Gary Taubes raises some good questions, but answers few.

Section one starts with an interesting history, but is quickly followed by a mishmash of claims, studies and counter-claims - all without a clear focus. It's almost as if Taubes knew what he wanted to say, but got so carried away with Google sludge, he forgot to tell US what it was.

Other than building an unwieldy foundation of references, the most powerful ideas in this first section are his descriptions of how "science" is driven by preconception, fashion, funding and politics. This IS an important lesson, but in no way validates his premise. Or even its converse. He just explains how distorted things can get. And Why. Which is a very good point. Then he proceeds to become his own best example.

His description of the specialist, and how they have trouble thinking outside their cubical, is useful. This is common in the engineering world and certainly a factor in medicine, biology and
nutrition.

Taubes describes selection bias nicely; then shows us how to use it. He talks about how bad science can be driven by fashion then does the very same thing in writing this book. Here's an
example...

He presents lipophilia as if it's still a valid hypothesis using the "fat-skin" graft to support the idea. Either he's being disingenuous, or he actually doesn't realize we don't increase the
NUMBER of fat cells as we gain weight - each existing cell simple scales up proportionally. This has been well extablished from observing the effects of liposuction and through other methods as well. Patients take on strange shapes if they lose or gain significant weight after the surgery.

Another recent study has verified, "The number of fat cells in a human's body, whether lean or obese, is established during the teenage years. Changes in fat mass in adulthood can be attributed mainly to changes in fat cell volume, not an increase in the actual number of fat cells."

Other research on the topic shows the body keeps the same number of fat cells for any individual, but obese people have about twice the number of fat cells as fit examples. This would indicate there IS a reason some people gain weight more easily than others, but Taubes doesn't dig into this important data. It doesn't fit with his metabolic disease theory. Instead he goes all the way back to lipophilia to make his point. This does not serve the millions honestly trying to deal with obesity.

Speaking of bad science, way too often Taubes quotes various researcher's stated conclusions from the distant past, when those people had far less information than would be available today. Would they have the same opinion? Were they valid opinions even at the time? Who knows. It doesn't matter. Opinions are only useful to guide speculative science and help define a hypothesis.

Fortunately, the book does get a little better. Once he starts explaining how all of this background matters in his quest for a cure of the disease of civilization, the pieces begin to fit together. In section two he raises (and explains) some very good points in the science of metabolism. His presentations on cholesterol, sugar and all of his "western" diseases is more readable but still a challenge. Still, it's hard to find conviction - almost as if he's trying too hard and presenting TOO MUCH data. Plus, once you find a few holes, he's hard to trust.

To make it worse, this is not a fun read. It's work. Taubes often slams ideas together in no meaningful order, then fails to present any conclusion. But IF you can drag yourself through it, there ARE some important ideas presented.

Taubes challening the idea that weight gain or loss is proportional to calories consumed and exercise performed is useful to think about. But he goes for a total disconnect which is naive. There IS a relationship. It's just not linear.

He also challenges many other ideas without disproving any of them. In "Paradoxes" he mostly muddies the water by challenging the definition of "overeating" as unscientific, but doesn't offer a better definition.

He then goes on to mix up and present physical, psychological and biological factors as a paradox. It's just muddled thinking, nothing more. He picks the most aberrant studies to discredit entire concepts. He does a "thought experiment" where a fat and a thin man each normally eating 3000 calories a day cut their intake in half to 1500 calories. When their weight doesn't fall proportional to their size or calorie deficit, he uses it to challenge the law of conservation of energy as invalid for humans. Again, bad science.

This classic over-simplification of a model is used to confuse the issue. What if 3000 calories were far MORE than either needed to maintain their weight? What if 1500 wasn't much less? I think it's clear that people vary widely as to the effects of cutting back. But that DOESN'T mean we can ignore how much we eat as long as it isn't carbs.

Taubes too easily dismisses exercise as a significant factor in weight loss by selecting his presentation. There are SO many poorly done "studies", you can select for almost anything. Which is another valuable point he didn't intend to make. But he does. He argues that the increase in carb consumption closely tracks our increase in weight, so it must be the cause. But our weight increase as a society also correlates with calories consumed, lack of exercise, number of fast food locations, miles driven and about a hundred other obvious factors. Here's just one recent example...

The Link Between Local Food Environments and Obesity and Diabetes.

His main point is, carbs are toxic because of the way they are metabolized - metabolic syndrome. But I'm not convinced.

I do agree that it's unlikely that all calories are created equal. They clearly have a different metabolic path to human storage or use as energy. But that in itself doesn't make some calories good, and some bad. The final answer will probably be more complex and in shades of gray.

The fattening of America IS a major problem, but mis-information won't help us solve it. And this book taken seriously would just make things worse.

Don't bother buying it.


Is Sugar Really Toxic? Sifting through the Evidence


For best of blog and other useful links...

Sudden.net