Study: No Evidence to Support Dietary Fat Guidelines
In a new systematic review, a team of researchers suggest that there is no evidence to support the recommendations put forth in national dietary fat guidelines geared toward reducing coronary heart disease.
Two sets of guidelines—introduced by the United States and United Kingdom governments in 1977 and 1983, respectively—stress limiting overall fat intake to 30% of total calories as well as reducing saturated fat to 10%.
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In its review, the team analyzed data taken from 6 randomized controlled trials involving 2,467 males, in which there were 370 deaths from all-cause mortality in the intervention and control groups. The investigators found no differences in all-cause mortality and non-significant differences in coronary heart disease mortality resulting from the dietary interventions. The reductions in mean serum cholesterol levels were much higher in the intervention groups, which did not result in meaningful differences in coronary heart disease or all-cause mortality, according to the authors, who note that government dietary fat recommendations were untested in any trial prior to being introduced.
When total fat and saturated fat are restricted, carbohydrate and unsaturated fat intake concomitantly rises,” says lead study author Zoe Harcombe, a researcher and PhD candidate at the University of the West of Scotland, adding that many recent publications have questioned current dietary guidelines.
Harcombe advises primary care physicians to encourage the consumption of real, whole foods such as meat, fish, eggs, dairy products, nuts and seeds, vegetables and fruits and whole grains; and to discourage the consumption of processed foods.
“The consequence of the dietary guidelines has been to drive people away from natural foods, which are naturally rich in the essential fats and fat soluble vitamins and other vital nutrients that we need to survive and thrive,” she says, “and toward manufactured foods [such as] breads, cereals, pasta, [and] low-fat/highly sugared products with little nutritional value.”
“We should not be demonizing any macronutrient if it comes from whole foods. That includes saturated fat,” noted James J. DiNicolantonio, PharmD, a cardiovascular research scientist at Saint Luke’s Mid-America Heart Institute, and co-author of the study.
If a patient is lowering their animal fat intake, “we need to be careful about what replaces that fat,” he adds. “If it is vegetable oils or refined carbs and added sugars, this will likely lead to worse health outcomes. However, if replaced by omega-3s (from fatty oceanic fish) or olive oil, there may be an overall benefit to our health.”
Ultimately, “eat real food” are the “3 best words for dietary advice” a physician can give to any patient, he says.
—Mark McGraw
Reference:
Harcombe Z, Baker J, et al. Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart. 2015.