Are high fat or ketogenic diets atherosclerosis-safe? | Lifestyle.INQ

OCTOBER 27, 2022

Last week we discussed the evolving concept that fats and oils, like coconut oil, may not be the major culprit behind clogged arteries that could lead to heart attack, stroke and cardiovascular disease (CVD).

Although conventional wisdom has been pointing to it as the main risk factor in the diet that causes this progressive narrowing of arteries, a consensus seems to be emerging, based on observational data, that a high-carbohydrate diet—which is the typical Filipino diet—may be a bigger risk factor in clogging arteries than fats and oils.

Could this be the reason CVD has remained the No. 1 killer in our country for almost three decades now?

Does this make fad diets like ketogenic diets, which are rich in fatty food and oils but low in carbohydrates, actually safer and relatively healthier than a low-fat, high-carbohydrate diet?

This is just one of the controversial issues to be tackled in the Asian-Pacific Society of Atherosclerosis and Vascular Diseases (APSAVD) Congress on Feb. 27-March 1, which the Philippine Lipid and Atherosclerosis Society (PLAS) is hosting in Iloilo City.

Medical controversies

Dr. Eugenio Ramos, PLAS president and overall congress chair, promises lively and interactive discussions on raging medical controversies.

Hopefully, the doctors attending the congress could go home with more pragmatic and accurate advice on what a healthy diet should consist of.

Erroneous advice

After the Prospective Urban Rural Epidemiology (PURE) study was published last year suggesting that a high-carbohydrate diet in more than 135,000 individuals from 18 countries, observed for an average of 7.4 years, was associated with more deaths compared to a high-fat diet, many patients somehow got the impression that their doctors have been giving them erroneous advice.

A patient quipped, in jest, “In this era of fake news, even doctors unwittingly become purveyors of fake advice.”

What seemed to be a paradox in the study was that those eating more saturated fats—the notorious type of fat abundant in animal fats and dairy products—but relatively less carbohydrates, had less strokes.

The fatty diet with saturated and unsaturated fats was also not significantly associated with a higher risk of heart attack or CVD-related deaths.

The researchers tracked the participants’ health and diet over the seven-year observation period, and were probably surprised themselves to find that those with the highest intake of dietary fats were less likely to have died than those with the lowest intake of fat. The opposite was noted with regards to the carbohydrate intake of the participants.

That’s how humbling the practice of medicine can be. It can swing to extremes like a pendulum, and treatments can also shift, based on the weight of available scientific evidence.

But we have to emphasize that the PURE study is considered an observational study, and needs to be further validated by more well-designed studies.

At a loss

In the APSAVD congress next week, highly respected endocrinologist Dr. Augusto Litonjua, considered the “Father of Philippine Endocrinology” and founding president of the Philippine Center for Diabetes Education Foundation, and equally respected clinical epidemiologist Dr. Antonio Dans, an advocate of evidence-based medicine in the country, will dissect this fat-and-carbohydrate controversy.

The PURE study really pulled the rug out from under doctors’ feet. Suddenly, clinical practitioners found themselves at a loss as to how to spin the findings and communicate them in a way that will not sound like a 180-degree turn.

Global dietary guidelines have also shifted, and all of a sudden, ketogenic or high-fat diets are increasingly popular.

The findings of the PURE study resonate with what Dr. Litonjua has been saying all these years, however. I had the privilege to chair a series of panel discussions in key cities in the country a few years ago, with Dr. Litonjua as main panelist-discussant.

This was before the publication of the PURE study. Dr. Litonjua was already telling the audience then that a high-fructose (carbohydrate) diet is the real reason people become fat and obese, and develop diabetes and metabolic syndrome—composed of high blood sugar, high blood pressure, cholesterol problems and increased belly fat.


Metabolic syndrome is strongly associated with increased risk of CVD. The PURE study somehow validated Dr. Litonjua’s hypothesis.

The findings of the PURE study are an eye-opener, but they must be seen in a more objective manner.

Whenever my high-risk heart patients ask me if they can start eating the previously forbidden crispy pata, bulalo, lechon fat and skin, I warn them that a single episode of high-fat bingeing could still land them in the emergency room or intensive care unit, and hopefully not in the funeral parlor.

Occasionally eating a bit of these food in moderation should not be risky, but regular bingeing could be a ticket to disaster.

High-fat diets may be relatively safe in young overweight individuals with no significant blockages of the arteries, but if one’s arteries are just marginally patent, the increased fat may be the final straw that could break the camel’s back.

Not conclusive

Like we said, the PURE study, being an observational study based on questionnaires, can offer some radically interesting findings that need to be further validated. As the term implies, it’s good in offering observations based on what was noted in the participants studied, but the findings cannot be considered conclusive.

There are also some methodological flaws in the study, like the extreme socioeconomic conditions for a significant number of participants from Third World countries. These extremely poor individuals rely mainly on carbohydrates as their source of nutrition, and don’t have adequate access to health care. Hence, they die early.

In contrast are participants in more affluent countries who eat more animal meat and other high fatty food but can afford to get adequate treatment when they get sick, and that can very well confound health outcomes in different populations.

So, the PURE study can only go as far as saying that it seems that a high fatty diet is linked with less deaths. It cannot, however, strongly state that findings conclusively show that a high-fat diet is safer and healthier, or that it’s the high-carbohydrate diet that directly causes increased deaths, strokes and heart attacks.

Other variables have not been factored in, and this could have distorted the findings.

In scientific discussions, I always try to temper the enthusiasm of some to jump on the bandwagon and recommend increasing fat in the diet. Doctors should tell their patients there’s no 180-degree turn in what is considered a healthy diet.

Healthy diet

A healthy diet should still consist of more vegetables, fruits (preferably low-fructose ones), whole grains, legumes, nuts, fish, low-fat dairy products and less refined grains, sweetened beverages and moderate amounts of unsaturated fats from plant sources rather than animal sources.

Wine may be allowed in moderation with meals—one shot or its equivalent amount (one bottle of beer or one glass of wine) for women, and two shots at most for men.

I’m looking forward to the discussions on this controversial issue during the APSAVD congress. If you are interested to hear more and share your opinion and insights, join the APSAVD congress in Iloilo next week.

Call 6962819 or 09176255810, or e-mail

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