Study: Lean Diets Don't Cut Disease Risk

A new study published in the most recent Journal of the American Medical Association suggests healthier diets don't necessarily lead to less chance of disease. The study followed more than 30,000 women restricted to low-fat diets, and concluded there was little or no evidence the diets led to lower rates of cancer and heart disease. Madeleine Brand speaks with Alice Lichtenstein, professor of nutritional science at Tufts University, about the findings.

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MADELINE BRAND, host:

This is DAY TO DAY. I'm Madeline Brand.

ALEX CHADWICK, host:

And I'm Alex Chadwick. Coming up, will '70s music icon Sly Stone actually show up at tonight's Grammy's?

BRAND: But first, Americans are fat, we all know that and now we know that eating a low fat diet won't necessarily change that or cut the risks of getting heart disease and cancer. In the largest study of its kind scientists tracked about 50,000 women for about a dozen years and they found no evidence that eating a low fat diet is healthier than eating a regular one. One researcher proclaimed this is the end of the low fat era.

And here to discuss whether that's true and to analyze the study is Dr. Alice Lichtenstein. She's a professor of nutrition science and policy at Tufts University. And Dr. Lichtenstein welcome to the program.

Dr. ALICE LICHTENSTEIN (Professor, Tufts University): Good to be with you.

BRAND: So it seems like common sense really that the less fat you eat the better off you'd be health wise and body wise, so were the results of this study surprising to you?

Dr. LICHTENSTEIN: They weren't surprising but I don't think it's necessarily common sense that the less fat you eat the less you weigh or the less disease you're going to have. I think what's really important is the total number of calories and it's an important message I think we have to be a little more careful about getting across.

BRAND: Well, I think a lot of people would be surprised to think that a calorie from a doughnut means about the same thing as a calorie from an apple.

Dr. LICHTENSTEIN: Well, not necessarily. What we know is a calorie is a calorie and the important thing is the total number of calories that you consume. Now, a gram of fat has about nine calories whereas a gram of protein or carbohydrate has about four calories. So you can eat a larger volume of let's say the apple as opposed to a high fat food, but the bottom line is it's the total number of calories you consume, the total amount of energy you expend and that's going to determine how much you weigh.

BRAND: Now, this study did not distinguish between so-called good fats and bad fats and I'm wondering are there any studies that do and if their findings contradict the findings of this study?

Dr. LICHTENSTEIN: There are a number of studies that have looked at type of fat and what we know is that saturated and trans-fatty acids will increase LDL cholesterol, which is related to the development of heart disease, whereas poly and mono unsaturated fatty acids will decrease LDL cholesterol level, hence risk of developing heart disease.

BRAND: Do you see any flaws in the methodology of this study?

Dr. LICHTENSTEIN: No, I actually think it's a study that was very well done. I think when it was planned the focus was on the total fat content of the diet and we have our answer. Since that time we've learned that type of fat and the total number of calories is far more important.

BRAND: But are you concerned that Americans will just see the headlines today and think well ok, it's ok now to go to McDonald's and gorge on hamburgers and French fries.

Dr. LICHTENSTEIN: Well, I think what Americans need to do is really embrace the concept that it's energy balance. It's the total amount of calories you consume and calories you burn. And you can have your cake and eat it too. So, going to McDonald's is not necessarily going to be a good idea if you choose one of the burgers and fries because it's going to be relatively high in saturated and trans-fatty acids and we know that's going to be associated with increased risk of heart disease.

I think what we need to do is make good choices, make the right choices with respect to fat which would mean limit intake of animal fat and hydrogenated fat and that'll take care of the trans and saturated fatty acids and then substitute, don't add, but substitute mono unsaturated and poly unsaturated fatty acids which come from things like canola and corn oil.

BRAND: And Dr. Lichtenstein I'm wondering, are you going to change your diet at all because of this study?

Dr. LICHTENSTEIN: Well, I've been aware of the research that has been coming out since this study was conceived so I'm consuming a moderate fat diet that's high in fruits and vegetables, whole grains, legumes, low fat and nonfat dairy products, fish and lean meat. So I think I'm going to stick with that and try to keep myself exercising.

BRAND: So what does that mean for tonight's dinner? What's on the menu?

Dr. LICHTENSTEIN: Tonight's dinner will probably be salmon and then I think there's going to be some steamed snow peas and then probably sauté that with some fresh spinach and brown rice.

BRAND: Mm. That sounds admirably health. No ice cream?

Dr. LICHTENSTEIN: Not an ice cream person, but I have an outstanding pineapple that's waiting to be consumed.

BRAND: Ok. Dr. Alice Lichtenstein is a professor of nutrition science and policy at Tufts University. Thank you.

Dr. LICHTENSTEIN: It's been a pleasure.

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