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Conclusion of diet study not as it seems

Published October 09. 2010 09:00AM

Although hundreds of novels are published each year in more than a half dozen genres, you can argue that at the core of each whether it be science fiction, mystery, or romance is one of two conflicts. Either the main character battles an external force, such as another character or nature, or the main character battles an internal element, such as a doubt or a demon, inside himself.

Something similar can be said about diet books.

Although dozens of different ones arrive at book stores every year, at the core of each is one of two strategies. The eating plan either reduces the amount of carbohydrates or reduces the amount of fat.

That's it. Look past the clever marketing and the key foods and every diet is essentially a variation of low carb or low fat.

So which is better for you?

I can't say for sure. That depends on a number of factors unique to you: your goals, your current health status, and your body type.

What I can say for sure is that you need to read any media account about research on the two diets carefully and critically.

In August, for instance, I read two articles on the Internet: "Low-Carb, Low-Fat Diets Each Work" and "Low Carb Diet Better For Cardiovascular Health Than Low Fat Diet."

The surprise? They were both reports about the same study published in Annals of Internal Medicine.

The first accentuated the fact when 307 obese people limited their caloric intake to 1,800 calories a day for two years, they lost the same amount of weight at the one-year and two-year mark whether the diet was what the researchers deemed low in carbs or fat.

The second stressed that the 154 obese subjects who followed the low-carb diet had better cholesterol and blood pressure readings after three, six, and 12 months than the 153 obese subjects on the low-fat diet, thereby making them less likely to have heart-related problems.

This second finding is especially noteworthy since the initial concern about following low-carb plans such as the Atkins diet long-term was that the high percentage of fat ingested could eventually lead to heart problems.

But in my mind there's something here just as notable, and it explains why the low-carb diet did more to promote heart health than the low-fat diet. Quite simply, the study was an unfair fight.

The low-carb diet followed by the 154 obese subjects who recorded better cholesterol and blood pressure levels was what I'd call a true low-carb diet. Subjects were limited to 20 grams of starchy carbohydrates a day for three months, the amount Atkins advocates in his strict two-week Induction Diet phase in "Dr. Atkins' New Diet Revolution" and about the amount of starchy carbs found in a single medium-sized baked potato.

But the low-fat diet while lower in fat by about seven percent than the typical American diet was not truly low-fat. It permitted 67 grams of fat per day, more than three times the amount Dr. Dean Ornish suggests in the Life Choice diet in his low-fat diet book, "Eat More, Weigh Less," and 3 grams less than the amount found in two McDonald's Big Macs.

So what's really surprising here is that the not-so-low-fat, low-fat diet didn't cause blood cholesterol and blood pressure levels to increase, not that the low-carb diet improved them.

But you'd never reach that conclusion or even know the parameters of both diets if you didn't read both articles carefully and critically.

So now that you've been warned that some of the most important information in a diet study might be buried at the bottom of a media account or not even covered at all, here's another issue: the lack of clarity created by the sheer number of health-related studies.

Three weeks after the Annals of Internal Medicine published the aforementioned article, the Journal of Nutrition published one that found supplementing a low-fat, high-carb diet with fish oil negated the rise in cholesterol found in the first with the subjects on the low-fat diet.

In this study, lead by Dr. Jose Lopez-Miranda, professor of medicine at the Reina Sofia Hospital at the University of Cordoba, Spain, had 117 subjects consume the same number of calories for 12 weeks while adhering to one of four types of diets: high fat and rich in saturated fat; high fat and rich in monounsaturated fats; low fat and high in complex carbs; low fat and high in complex carbs but with a supplementation of 1.24 grams of fish oil daily.

That final group did not experience the rise in cholesterol and triglyceride levels that the other low-fat group recorded.

In essence, one small change changed the previous findings established less than a month before.

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