Niki Bezzant: What's worse - carbs or fat?

Is a bit of butter better - or a bit of bread? Photo / 123RF

Opinion

Which is worse: carbohydrate or fat? Is it the bread or the butter that's going to kill us?

That's the narrative that's done the rounds again recently, after the results of a large study hit the headlines.

The PURE study (Prospective Urban Rural Epidemiology) included 135,335 people from 18 countries across five continents who were followed for seven years.

The researchers assessed dietary intakes and recorded who died from cardiovascular disease and other causes. In the most recent paper they assessed the percentage of energy in the diet from carbohydrates, fats and protein, and from different types of fat.

Among the conclusions were that people who ate the most carbohydrate - mostly in China, South Asia and Africa - had a higher risk (28 per cent higher) of death - although not from cardiovascular disease - compared to the people who ate the least carbohydrate.

The people who ate the most fat, on the other hand, had a 23 per cent lower risk of mortality than the people who ate the least fat.

On the surface, this looks like a high-five for low-carb, high-fat promoters. Some of the headlines reflected this.

The media across the globe is always attracted to novelty, and the idea of challenging conventional wisdom - "everything we've been told is wrong" - was just too appealing for many to resist. "Butter, cream and cheese could help us live longer," reported Australia's Channel Ten breathlessly.

Of course, as in all science, it's never the case that one study negates everything that has come before. And this one hasn't, either. It does add nicely to what science knows about eating for health and longevity, though.

Delving into the detail, we discover that the high carb eaters in the study were eating a very high carb diet - 77 per cent of energy from carbs. The low carb eaters got 46 per cent of their energy from carbs. And the high fat eaters were eating a not-alarmingly-high amount of fat - 35 per cent of energy.

According to the most recent National Nutrition Survey, New Zealanders' mean intakes of fat and carbs are 34 per cent and 47 per cent, respectively. Based on these definitions, the average Kiwi is actually eating low carbs and high fat.

As we all know, of course, Kiwis are by no means all eating perfectly for optimal health.

There's a danger in focusing on nutrients, not food. The diet recommended by the researchers in their conclusions - 50-55 per cent carbohydrates, 35 per cent fat, and 10-15 per cent protein - closely resembles the Mediterranean diet, well-established as healthy. And, in fact, it's not so different from the healthy eating guidelines in New Zealand, although 15 per cent energy from protein is the minimum recommended.

But although we seem to be adhering to the guidelines in terms of nutrients, clearly we could do a lot better in terms of food, and the quality of what we're eating. As some experts have pointed out, there's a big difference between types and qualities of carbohydrates, and this was unfortunately something this study didn't address.

Getting our carbs from vegetables, fruits, whole grains and legumes is a whole lot better than getting them from refined white rice and white bread. There's a difference between green beans and jellybeans.

Perhaps the better headline for this research is the one used by the researchers themselves in their press release, "Moderate consumption of fats, carbohydrates best for health, international study shows".

Not great clickbait. But perhaps more helpful for our health.

* Niki Bezzant is editor-at-large for Healthy Food Guide magazine.