Meat and cheese lovers may have gotten excited recently when an article in the Washington Post was published with the headline “Atkins diet’s return reflects idea that saturated fat shouldn’t be demonized.”
No doubt the Washington Post got excited, too, because there’s no better way to pick up flagging newspaper sales than to tell people that it’s okay to eat the foods they love.
Sorry, Washington Post, but it’s NOT okay to eat foods high in saturated fat like red meat, cheese, butter, and full-fat ice cream.
Is saturated fat bad for you and your heart? Yes.
We know beyond any reasonable doubt that increased saturated fat intake raises LDL cholesterol levels; and over time, higher LDL levels promote more atheroclerosis and cardiovascular-related mortality.
To bolster this ridiculous claim, the Post referred repeatedly to a study published in the March issue of the American Journal of Clinical Nutrition. The study analyzed several epidemiological studies (the studies’ lengths ranged from 5 to 23 years) and found no significant evidence that dietary saturated fat is linked with an increased risk of cardiovascular disease.
But here’s the problem: It has always been very difficult to find any significant correlation between saturated fat intake and cardiovascular disease using epidemiological data within a given population. The reason is not because a correlation does not exist but because of the way people’s eating habits are measured. In these epidemiological studies, scientists used dietary recall data, “but dietary recall data are very inaccurate,” points out Dr. Jay Kenney, Nutrition Research Specialist at the Pritikin Longevity Center.
In numerous investigations on the efficacy of 24-hour dietary records, scientists have found that the majority of people cannot estimate their food intake, or forget what they have eaten, or outright lie (Who wants to admit they wolfed down two cheeseburgers for lunch?).
And even when 24-hour food recalls are fairly accurate, they are still highly suspect as a measurement of people’s overall food intake.
First of all, people often eat very different amounts of saturated fat from day to day. The day they recorded their sat fat intake may have been the day they had bean chili for dinner. The next day (the day that was not recorded) may have ended with a sirloin steak and crème brulee.
Secondly, people often change their diets over time, especially in industrialized countries like the U.S. Hence, what their daily diet was at the beginning of a 10-year study may have changed significantly two, three, or five years into the study.
“The point is: When your measurements of dietary variables are very inaccurate – and when you have no scientific tool to measure subjects’ eating habits over long periods of time – the odds of finding a significant correlation, even if one exists, go way down,” states Dr. Kenney.
Of course, if we study the actual cultures and eating habits of populations that we know eat far less saturated fat over their lifetimes, we see much lower levels of cholesterol in these populations, and much lower levels of cardiovascular events like heart attacks.
Here are two examples:
Researchers traveled to Okinawa and for years tracked the daily eating habits of the people living on this island off the coast of Japan. It was easy to confirm that Okinawa’s people ate very little saturated fat because there wasn’t much of the fat on the island to begin with. The population followed a diet (as they had for centuries) that was high in unrefined carbohydrates like fruits, vegetables, and whole grains. They ate up to 20 servings of unrefined carbohydrates daily. Staples included sweet potatoes, dark green vegetables, green peppers, rice, fresh fruit, tofu (and other forms of soy), as well as seafood rich in omega-3 fatty acids. While fish made up about 11% of the diet, only about 3% came from saturated-fat-containing foods like poultry and meat.
On this very low-in-saturated-fat diet, Okinawa’s citizens were found to have 80% fewer heart attacks than Americans. They were also lean (Take that, Atkins diet proponents), averaging a body mass index of just 22. There’s more good news: They had (and still have) the longest disability-free life expectancy in the world. They also have the highest percentage of citizens over the age of 100. Is there a correlation here between low-in-saturated-fat diets and very low rates of heart disease? You bet.
The China Study
Heralded as the most comprehensive study of diet and disease ever conducted, the China Study by Cornell University scientists looked at 16,700 individuals in the 65 provinces of China over a six-year period in the 1980s. It examined more than 1,000 separate diet, lifestyle, and environmental aspects relating to each of the subjects.
The provinces with the least amount of cardiovascular disease were those following a very low-fat diet (about 15% of total calories) rich in unrefined carbohydrates. Saturated fat intake was very low (less than 5% of total calories), which certainly made sense. In these provinces, McDonald’s and other saturated-fat-rich establishments were few and far between. Instead, fruits, vegetables, rice, and other grains were dietary staples, comprising 77% of total calories. Daily fiber intake was about three times that of Americans. Total cholesterol levels averaged 135 to 140.
One of the many conclusions of the China Study was that the more developed a region became, the more meat and dairy products (saturated fat) its citizens consumed, and the higher their cholesterol levels rose. Likewise, the rates of heart disease, diabetes, and cancer were higher in these more affluent regions.
By contrast, “The people of China who ate the most plant-based foods and the least saturated fat were the healthiest and tended to avoid chronic disease. These results could not be ignored,” concluded lead author Colin Campbell.
Other results that cannot be ignored are those of short-term studies where saturated fat intake is carefully controlled. “The data consistently show that lower saturated fat intake correlates with lower LDL bad cholesterol levels,” sums up Dr. Kenney.
Bottom Line: We know beyond any reasonable doubt that increased saturated fat intake raises LDL cholesterol levels; and over time, higher LDL levels promote more atheroclerosis and cardiovascular-related mortality. The only thing this recent American Journal of Clinical Nutrition study showed is that current dietary assessment methods often yield very inaccurate data.
One last word about the new Atkins diet book. You’ve really got to wonder about its authors, particularly the one quoted extensively by the Washington Post – Eric Westman, MD. Says Dr. Kenney: “I met Dr. Westman and discussed important research authored by Peter Kwiterovich, MD, of Johns Hopkins Medical Institutions, which found that a high-saturated-fat diet caused huge increases in LDL cholesterol levels in children. Dr. Westman replied that perhaps kids respond differently to saturated fat intake than adults do. WRONG. He had no rational rebuttal and was completely oblivious to the errors in his studies and those of other Atkins supporters.”