From LA Times
After shifting fads, time for a clear-eyed look at fat in our diets
Oils from walnuts, avocados and fish are among the more healthful fats.
By LILY DAYTON | March 7, 2015
th national headlines touting the message that low-fat diets are out and high-fat diets are in, people who once shunned butter are slathering it on toast, melting it in sautés and even plopping it into their coffee. And though the media has glorified saturated fat, it turns out that the main problem with the past decades' low-fat trend is that it has been misinterpreted.
"There is no real low-fat controversy," says Dr. David Heber, founding director of the UCLA Center for Human Nutrition. "The problem wasn't low fat; the problem was that when we lowered fat content, we increased carbohydrate and sugar content." Heber gives the classic example of SnackWells fat-free cookies, popular in the 1990s. With zero fat, SnackWells were considered more healthful than regular cookies, but they were only palatable because they contained high amounts of refined sugar and carbohydrates.
The low-fat fad emerged in the 1980s, following a growing body of research that linked a diet high in fats to increased cardiovascular disease risk. The U.S. Department of Agriculture's food pyramid reflected the wisdom of the time: The base showed bread, rice and cereal, which Americans were urged to eat plentifully; the tip of the pyramid depicted fats and oils to be used sparingly. Breakfasts of eggs and bacon were replaced with bowls of cereal; steak dinners were swapped for plates of pasta.
By the 2000s, mounting evidence showed that different fats had differing health outcomes. Saturated fat in particular was associated with increased cardiovascular disease risk, and unsaturated fats were shown to have a protective benefit.
Then, in 2014, a controversial meta-analysis published in the Annals of Internal Medicine was widely misconstrued to promote a diet high in saturated fat. Newsstands screamed, "Eat butter," and the saturated fat trend gained momentum. But in reality, the analysis showed not that saturated fat is good for us but that, when compared with diets low in fat but high in refined carbohydrates, a diet high in saturated fat is almost a wash in terms of cardiovascular disease risk.
Aside from misinterpretations of study results, the analysis itself had fundamental errors that prompted an international outcry from scientists. The authors had mixed up the results of one study they analyzed, omitted key studies from their analysis and failed to mention what people consumed as replacements when they ate less saturated fat. A corrected version of the paper was posted on the journal's website.
"When talking about diets, we always have to think about what the trade-off is," says Dr. Frank Hu, professor of nutrition and epidemiology at Harvard School of Public Health. "If you cut back on saturated fat, you're going to replace it with either unsaturated fat or carbohydrates. The type of replacement can have a major impact on health outcomes."
Diets low in fat and high in refined carbohydrates are associated with increased triglycerides and decreased levels of HDL ("good" cholesterol), factors that are linked to metabolic disorders and cardiovascular disease. Since the low-fat trend of the 1980s, rates of obesity and type 2 diabetes have skyrocketed, and heart disease is still the No. 1 cause of death in America.
Read more from LA Times >>
After shifting fads, time for a clear-eyed look at fat in our diets
Oils from walnuts, avocados and fish are among the more healthful fats.
By LILY DAYTON | March 7, 2015
th national headlines touting the message that low-fat diets are out and high-fat diets are in, people who once shunned butter are slathering it on toast, melting it in sautés and even plopping it into their coffee. And though the media has glorified saturated fat, it turns out that the main problem with the past decades' low-fat trend is that it has been misinterpreted.
"There is no real low-fat controversy," says Dr. David Heber, founding director of the UCLA Center for Human Nutrition. "The problem wasn't low fat; the problem was that when we lowered fat content, we increased carbohydrate and sugar content." Heber gives the classic example of SnackWells fat-free cookies, popular in the 1990s. With zero fat, SnackWells were considered more healthful than regular cookies, but they were only palatable because they contained high amounts of refined sugar and carbohydrates.
The low-fat fad emerged in the 1980s, following a growing body of research that linked a diet high in fats to increased cardiovascular disease risk. The U.S. Department of Agriculture's food pyramid reflected the wisdom of the time: The base showed bread, rice and cereal, which Americans were urged to eat plentifully; the tip of the pyramid depicted fats and oils to be used sparingly. Breakfasts of eggs and bacon were replaced with bowls of cereal; steak dinners were swapped for plates of pasta.
By the 2000s, mounting evidence showed that different fats had differing health outcomes. Saturated fat in particular was associated with increased cardiovascular disease risk, and unsaturated fats were shown to have a protective benefit.
Then, in 2014, a controversial meta-analysis published in the Annals of Internal Medicine was widely misconstrued to promote a diet high in saturated fat. Newsstands screamed, "Eat butter," and the saturated fat trend gained momentum. But in reality, the analysis showed not that saturated fat is good for us but that, when compared with diets low in fat but high in refined carbohydrates, a diet high in saturated fat is almost a wash in terms of cardiovascular disease risk.
Aside from misinterpretations of study results, the analysis itself had fundamental errors that prompted an international outcry from scientists. The authors had mixed up the results of one study they analyzed, omitted key studies from their analysis and failed to mention what people consumed as replacements when they ate less saturated fat. A corrected version of the paper was posted on the journal's website.
"When talking about diets, we always have to think about what the trade-off is," says Dr. Frank Hu, professor of nutrition and epidemiology at Harvard School of Public Health. "If you cut back on saturated fat, you're going to replace it with either unsaturated fat or carbohydrates. The type of replacement can have a major impact on health outcomes."
Diets low in fat and high in refined carbohydrates are associated with increased triglycerides and decreased levels of HDL ("good" cholesterol), factors that are linked to metabolic disorders and cardiovascular disease. Since the low-fat trend of the 1980s, rates of obesity and type 2 diabetes have skyrocketed, and heart disease is still the No. 1 cause of death in America.
Read more from LA Times >>
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