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Another Nail In The Coffin

...of the low-fat diet myth:

Although participants actually decreased their total daily calories consumed by a similar amount, net weight loss from the low-fat diet after two years was only 6.5 lbs. (2.9 kg) compared to 10 lbs. (4.4 kg) on the Mediterranean diet, and 10.3 lbs. (4.7 kg) on the low-carbohydrate diet. "These weight reduction rates are comparable to results from physician-prescribed weight loss medications," explains Dr. Iris Shai, the lead researcher.


The low-fat diet reduced the total cholesterol to HDL ratio by only 12 percent, while the low-carbohydrate diet improved the same ratio by 20 percent. Lipids improved the most in the low-carbohydrate, with a 20% increase in the HDL ("good") cholesterol and, 14% decrease in triglycerides. In all three diets, inflammatory and liver function biomarkers was equally improved. However, among diabetic participants, the standard low-fat diet actually increased the fasting glucose levels by 12mg/dL, while the Mediterranean diet induced a decrease in fasting glucose levels by 33mg/dL.

I've blogged about this before, but I continue to be amazed and frustrated at the ongoing ignorance in the medical and dietetic community about this. They persist in thinking that it is a simple thermodynamics problem--all calories are equal--and will not accept the notion that what we eat can affect our metabolism (how fast we burn energy, and how much it influences how we burn body fat).

It's why I pay no attention to either physicians, or nutritionists (or the FDA), when it comes to dietary advice. As Glenn says, it's fortunate that I also like a Mediterranean diet.

 
 

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14 Comments

DensityDuck wrote:

The problem is that is IS a thermodynamics equation for most people. People think that "eating healthy" is better than "eating less"--and so they cram themselves full of "healthy" food. It's like the old joke about the lady who drank eight Slim Fast shakes a day and couldn't figure out why she was gaining weight...

Carl Pham wrote:

Pssht, Rand, you're unfair, and painting those communities in cartoonish terms. I don't think any doc or dietician is going to quibble if you want to diet the "Mediterranean" or "low-carb" way as long as your total caloric intake drops. You're certainly right that it isn't just a thermodynamics problem, but on the other hand, losing weight certainly starts with a thermodynamic solution. As DD points out, you can't lose weight on a "low-carb" or "Mediterranean" or any other kind of diet unless, as condition #1, it involves eating fewer calories.

No doubt, changing the type of foods you eat can affect your motivation, how fast you lose weight, and can probably change the degree to which your weight loss translates into health improvement. But changing the types of foods you eat without reducing the total calories isn't going to do dick, and I think that is the message these communities are dedicated to promulgating.

Because, as again DD observes, people passionately long for a diet system that lets them merely switch categories of foods and not reduce total calories. Until you can get every dieter to admit the unpleasant truth that losing weight necessarily means fewer total calories, period, end of story, there may be little point to observing that, yes, there are different ways of reducing calories, and some of them may make it easier for you to stick with the plan, and some of them may bring you health benefits (e.g. lower LDL) faster.

Paul Milenkovic wrote:

First of all, unless we are experiencing a very rapid weight gain or loss, most of us are in a kind of dietary homeostasis of where caloric intake is balanced by metabolic caloric consumption. A lot of us who have packed on the pounds with age have done this slowly over fairly long periods of time. Perhaps you have heard the advice that the extra caloric input of one pat of butter per day over X-years results in Y-pounds of weight gain.

Perhaps most of us with middle-age weight gain have acquired this weight over long periods of time without any particular kind of binge eating or bad habits owing to the cumulative effect of a slight imbalance in this dietary homeostatis.

OK, we have gotten the fear of middle-age cardiac death or Type-II diabetes into us and want to shed some of the pounds. The engineer-geek answer "Eat less." Such a simplistic analysis of a complex system -- I hope you engineer types approach your payed-for work with some higher level of sophistication.

We have evolved to protect ourselves from starvation. A simple reduction in caloric input through following the simplistic prescription of "Eat less" is going to trigger symptoms of starvation. Once that kicks in, forget will power, diet: some form of binge eating will kick in to get over the supposed crisis that our bodies are programmed by evolution to respond to.

How can I make this more plain: following a weight reduction plan of simply invoking willpower and resolving to "Eat less" is a sure-fire way to gain weight. Yes, you heard me, gain weight. Anything stupid like that will trigger the starvation response and binge eating to compensate.

That is where these Atkins Diets and Mediteranean Diets come into play. There is calorie reduction, yes, but it is carefully controlled calorie reduction so as to not trigger the starvation reflex. Low-fat is unhelpful in this regard because low-fat is often high-carb, and satisfying hunger pangs with a dose of carbs is a sure-fire way to make yourself even more hungry.

There had been this rating of foods by their "glycemic index", and interestingly enough, eating a bowl of rice or a slice of bread without anything (high fat) on it -- from a glucose and Type-II diabetes standpoint, you may as well be eating out of the sugar bowl.

I have come to the belief that food or psychological triggers that bring on hunger pangs, what they are doing is triggering anticipatory bursts of insulin. Probably the healthiest thing to do for the somewhat plump middle aged is to treat yourself as if you are a Type-II diabetic and engage in eating patterns to avoid those bursts of insulin. The Diabetes Association with their complex carbs advice is probably off base and the Atkins/Mediteranean Diet people probably are more on track in this regard.

Rand of course explained this in so many words in his parent post, but the self-righteous weight experts, ready to hector us with "Eat less", have apparently leaked over from Megan McArdles Veganland to Rand's site.

Mike Puckett wrote:

I have found when I eat lots of sugary or carb heavy foods, I want to eat more of everything, I stay hungary more of the time.

When I eat higher fat foods and shun sugar, I don't go around craving stuff all the time.

I suspect this is insulin related.

Mike Puckett wrote:

Make that Hungry, not the country.

Carl Pham wrote:

Geez, Paul, are you talking to me? 'Cause actually I agree with you. If you're an overweight middle-aged fart, I think the advice to treat yourself as an incipient type II diabetic and avoid high glycemic foods is spot on.

TBinSTL wrote:

My Father, a practicing physician, tells me that he would estimate at one time he figured over half of his colleagues were doing the "low-carb" thing. They didn't talk out loud about it but in the physicians lounge, the meat was constantly being replenished while bread and potatoes and starchy vegetables were going relatively untouched.
The point being that they knew that they would open themselves to criticism if they spoke of it or recommended it but they chose it for themselves. Quite telling if you ask me, which you didn't, but there it is.....

Brock wrote:

Too bad Carl, DensityDuck and Paul don't know what the hell they're talking about.

We're talking about obesity here, and obesity is not (primarily) a calorie/thermodynamics problem. The thermodynamics only become a problem once your blood and hormone profiles get totally fuhked by the standard Western diet. Fix those and the calories become a 99% non-issue (they matter, but barely).

Google yourselves some Garry Taubes and watch the lectures, read the articles, etc. Then read this to see why homeostasis and "set point" theories are bunk:

www.arthurdevany.com/webstuff/WhyWeGetFat.pdf

Josh Reiter wrote:

Don't forget the issues of cardiac health as well. The DASH diet is really a Mediterranean diet that watches the salt.

Really, what I would suggest is to reasonably eat what you like -- just do more. My Fiance has been working on getting into her wedding dress and she signed up for training through 24 Hour Fitness. They got her to use the BodyBugg which is a device that straps around the back of your arm. It has a pedometer, an accelerometer, detects sweat, and measures skin surface temperature. You then upload your information stored in the data logger to your computer through a wireless sync and it will instantly show your caloric burn. You can then plug in the food you've eaten to compare input/output. One thing she has noticed is that just changing little things in her daily patterns has made huge differences in how many calories she burns. Like, taking the stairs over the elevator. Or, parking further out in the parking lot at Walmart. Even just fidgeting while she is sitting in a chair increases caloric burn. She knows this because the BodyBugg actually will do an hour by hour breakout. She can see when she was at her desk during the afternoon tapping her foot. It really is a marvelous piece of technology. Since she has gotten her's I have begun to notice more and and more people around my work place that have been wearing them as well.

Jane Bernstein wrote:

Perhaps you will all tolerate a few words of advice from this physician.

I work in aesthetics and get asked for weight loss advice fairly often. My own profile is around 13-15% body fat, and I have a very disciplined exercise schedule. The best consistent advice I give people is "It's 90% diet." Esoterica about how much activity expenditure in the course of your day takes place, or whether you should lift weights with heavy loads and low repetitions or the other way around really misses the point. Manage diet.

I tend to tell people to do the following things:

1: Eat oftener, but smaller. Four to six smaller meals is better than two to three large ones.

2: Eat lean protein at every meal. Animal protein is preferred.

3: Eat a vegetable - a green one - at every meal.

4: Have a piece of fruit if you like as well.

5: If you're going to eat something made of fast carbohydrates (corn, bread, wheat products, tortillas - that sort of thing) do it only within an hour of exercise. There's some physiologic reasons that this makes sense having to do with recovery and replenishment, but I personally think the biggest benefit is just being mentally engaged with what you're eating and when. Plus it encourages actual exercise.

6. Lose the beverages that contain calories.

7. Get around 35% of your calories from fats. Just make sure they're the right kind. Fish oil, monounsaturates, and good "animal source" saturated fats are okay.

8: 90% compliance with these rules is as good as 100%. There's no statistical difference. So budget your cheating.

My patients have seen results in their lipid profiles, following this advice, that rival being put on Lipitor.

Rand Simberg wrote:

There's some physiologic reasons that this makes sense having to do with recovery and replenishment, but I personally think the biggest benefit is just being mentally engaged with what you're eating and when.

Yes. I don't really diet, per se (in terms of worrying about how much I eat) but I pay a lot closer attention to what kinds of things I eat than I did when I was young. I have cut way back on high-glycemic carbs, and haven't had a soft drink in years, and I think I'm doing pretty well.

DensityDuck wrote:

Every piece of diet advice I've ever seen boils down to "portion control" and "physical activity". You can tart it up with "glycemic index" this and "saturated fats" that, but in the end it's all about the calories.

But people desperately want a magic bullet for weight loss. The notion of discipline is completely foreign to them.

Rand Simberg wrote:

..in the end it's all about the calories.

No. That's one of the points that this study makes. It is not all about the calories. It's all about how you burn the calories that you intake.

DensityDuck wrote:

*sigh*

...which is, in fact, about the calories. Unless burning calories is not actually about calories but in fact about something else, perhaps hamsters, or possibly the color blue.

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This page contains a single entry by Rand Simberg published on July 17, 2008 2:34 PM.

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