Dietary Fat Guidelines Go Under the Microscope

Dietary fat intake guidelines for US and UK may not be supported by evidence

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Expert health guidelines are generally accepted and widely followed, but new evidence suggests one set of guidelines might be pointing patients in the wrong direction.

A new review found that long-held guidelines about fat consumption were not backed by sufficient evidence. The authors of this review said it's possible that these guidelines should never have been released.

In an interview with dailyRx News, Deborah Gordon, MD, a nutrition expert based in Ashland, OR, applauded the findings.

"There never was good evidence for making fat reducing suggestions to the general public, and it is conceivable that the advice has caused far more harm than good," Dr. Gordon said.

According to the authors of this review, led by Zoë Harcombe, of the University of West Scotland's Institute of Clinical Exercise and Health Science, the guidelines in question were released in an attempt to reduce coronary heart disease.

According to Harcombe and team, the US government suggested that fat intake should be reduced to lower heart disease risk in 1977. The United Kingdom (UK) did the same in 1983.

However, these researchers argue that, so far, no evidence has been found to support these guidelines.

Harcombe and team assessed a number of trials that were finished before the guidelines were introduced in the UK in 1983. These trials all involved fat in the diet, cholesterol levels and heart disease.

These researchers found six trials that would have been available at the time the guidelines were introduced. These studies involved nearly 2,500 men and lasted an average of 5.4 years.

Among those in these studies who reduced their fat intake, 207 died from heart disease. Among the control patients whose diets did not change, 216 died from the condition.

The rate of death from heart disease was not found to be affected by reducing fat intake — nor were rates of death from any cause.

Harcombe and team also noted several limitations of the trials. For instance, the patients were all men, and many were unhealthy when they entered the trials.

Dr. Gordon said the release of these guidelines could have had unintended results.

"It has been widely observed that fat reduction has been met with carbohydrate increase," Dr. Gordon said. "One might have theorized that possibility: removal of the savor of fat and you need to replace it with something that will please our palates, and that something has been sweets. Or one may just rely on the data. Our protein consumption has stayed constant, fat actually declined, and carbohydrates have been chowed down in excess."

Dr. Gordon said she has seen the effects of lowering carb intake first-hand.

"In my own practice and personal experience, it has certainly been true that [cardiovascular] risk markers (obesity, insulin resistance, and hypertension) have been far more promptly and drastically reduced as carbohydrates were shunned," Dr. Gordon said. "And yes, if you eliminate those tasty carbs, you must substitute other flavorful foods: I recommend pasture-raised butter and meats, olive oil and avocados, and full-fat dairy if it suits you."

In an editorial about this study, Rahul Bahl, MD, of the Royal Berkshire NHS Foundation Trust in Reading, UK, wrote that this study doesn't necessarily mean the guidelines should be disregarded. Dr. Bahl said further thought and research should be given to this complex topic.

"There is certainly a strong argument that an overreliance in public health on saturated fat as the main dietary villain for cardiovascular disease has distracted from the risks posed by other nutrients such as carbohydrates," Dr. Bahl wrote.

However, Dr. Bahl warned against removing the blame from one part of the diet and placing it solely on another.

The study and editorial were published Feb. 9 in the journal Open Heart.

The authors disclosed no funding sources or conflicts of interest.

Review Date: 
February 9, 2015
Last Updated:
February 10, 2015