Is food fat really that bad for you?

Recent research, published in online journal Open Heart, appears to point to the fact that national dietary advice on fat consumption issued to millions of UK citizens in 1977 and 1983 to cut coronary heart disease incidence lacked any solid trial evidence to back it up.

This issue of fat in our diet has long been debated by Skipton-based food expert Verner Wheelock. The former head of the University of Bradford’s Food Policy and Research Unit, who set up Verner Wheelock Associates, a food training and consultancy service based in Broughton Park, believes public health standards are deteriorating, as shown by the increase in obesity and particularly in Type 2 diabetes which he says has doubled in the last 15 years or so.

Verner said: “There is now convincing evidence that the major factor which has caused this is the dietary recommendations which were first devised in 1984. This set a target to reduce saturated fat (SFA) by 25 per cent which was achieved in 2000. We were also advised to increase carbohydrates and there could be some increase in the intake of the polyunsaturated fat (PUFA).”

Verner says many of the individual SFAs are valuable nutrients in their own right and adds that many individuals have in fact improved their health by adjusting to a diet which is low in carbohydrates and high in fat.

“Because many people have been trying to comply with the official advice, they have been making it worse for themselves,” he says. “Low fat products are formulated by taking out the fat and very often replacing it with sugar. Because sugar is cheap, it is now added to many processed foods so it can be very difficult to construct a diet which is low in sugar if many processed foods are used.”

According to the research, both sets of dietary guidelines recommended reducing overall dietary fat consumption to 30 per cent of total energy intake, and specifically, saturated fat to 10 per cent of total energy intake. Both acknowledged that the evidence was not conclusive.

In the absence of any analysis of the evidence used to corroborate the dietary recommendations, the researchers carried out a systematic review and meta-analysis of the randomised control trial data that would have been available to the US and UK regulatory committees at the time.

After a comprehensive search of research databases, they found six relevant trials, covering seven different dietary interventions, spanning an average of five years, and involving 2,467 men. All the trials had been published before 1983 and had looked at the relationship between dietary fat, serum cholesterol and the development of coronary heart disease.

Five out of the six did not consider either the overall or saturated fat recommendations. And all but one focused on secondary rather than primary prevention.

The researchers highlight several caveats in the evidence available at the time: no women were included, no trial tested the dietary recommendations and no trial concluded that dietary guidelines should be drawn up.

“It seems incomprehensible that dietary advice was introduced for 220 million Americans and 56 million UK citizens, given the contrary results from a small number of unhealthy men,” write the researchers.

“The results of the present meta-analysis support the hypothesis that the available (randomised controlled trials) did not support the introduction of dietary fat recommendations in order to reduce (coronary heart disease) risk or related mortality.

“Dietary advice not merely needs review; it should not have been introduced.”

Zoe Harcombe, a researcher involved from the University of the West of Scotland, says the paper should mean that we revisit dietary guidelines as a matter of urgency.

Amy Thomas, cardio vascular disease specialist dietician at Bradford Royal Infirmary, says she believes the message got too extreme and fat became associated with bad health and heart disease.

She says nutritionists also get hung up on the role of nutrients in disease. “But we never eat nutrients in isolation,” explains Amy. “We eat it in combination and it is the balance of the diet that is protective of our health, not one particular nutrient.”

She says the balance of the Mediterranean diet is a healthy way of eating including wholegrain foods, fruit and veg, lean meat and nuts and seeds.

She said: “We need to get back to good old wholesome home food cooking.”