Is Rice Really Worse Than Soda?

Yesterday, the Straits Times (ST) ran an article titled Diabetes: The rice you eat is worse than sugary drinks which came up several times in my social media feed. I was disturbed by the headline. Were you?

Then, an editor I regularly work with e-mailed to ask if I’d like to pitch related stories. She got me thinking deeper, and this is an edited excerpt of my reply to her:

The sugar > obesity > diabetes discussion is an interesting one to follow, and I think commercial pressures are influencing the conversation in a big way. (Related, read this great article by The Guardian titled The Sugar Conspiracy)

Personally, I think that white rice is being somewhat unfairly villanised, in part because the lobbying pressure is probably significantly less from the rice farmers than the big soda players.

I would be a bit more careful about framing the relationship between white rice and diabetes because
– There’s more to the Singaporean diet than local foods heavy in rice
– You’ll find a lot of added sugar in supposedly “healthier” low- and no-fat foods (sugar is added to make up for the loss of flavour)
– And there’s sugar in so many other things, from salted egg yolk sauce and ketchup to Frappuccino and salted caramel brownies

Also relevant to the discussion
– Should people eat more (lean) protein then?
– If so, can hawkers afford to change the proportions of rice to other (more costly) ingredients?

Back to the ST report. It says a Harvard study “showed each plate of white rice eaten in a day – on a regular basis – raises the risk of diabetes by 11 per cent in the overall population”.

The article also cites another study which suggests that “replacing 20 per cent of white rice with brown rice lowers your risk of diabetes by 16 per cent”.

So what exactly did researchers discover?

Curious, I looked up the research. Both were done by Harvard researchers. The first study, published in 2012, looked at 352,000 people from China, Japan, the United States, and Australia. Read the press release here and the journal article here.

A clearer statement of the mentioned finding is this: “For each serving per day increment of white rice intake, the relative risk of type 2 diabetes was 1.11.”

The original journal article also included a brief explanation as to why higher white rice intake is associated with a higher risk of type 2 diabetes: “The recent transition in nutrition characterised by dramatically decreased physical activity levels and much improved security and variety of food has led to increased prevalence of obesity and insulin resistance in Asian countries.

“Although rice has been a staple food in Asian populations for thousands of years, this transition may render Asian populations more susceptible to the adverse effects of high intakes of white rice, as well as other sources of refined carbohydrates such as pastries, white bread, and sugar sweetened beverages [ed: my emphasis].”

The second study on replacing white rice with brown was published in 2010, and its press release can be found here.

What do the numbers mean?

Recalling the statement in the ST article: “Each plate of white rice eaten in a day – on a regular basis – raises the risk of diabetes by 11 per cent in the overall population.”
It does not mean that 11 out of 100 Singaporeans could get diabetes from eating a big plate of rice daily, in case you thought so.

For the numerically-challenged (also me), theses articles (Understanding Risk: What Do Those Headlines Really Mean? and Absolute Risk and Relative Risk) can help you make sense of numbers mentioned in the ST report and similar health articles. I believe the risk mentioned in the article is relative risk. I shall now attempt to explain:

Let’s suppose, hypothetically, that the mentioned risk applies in Singapore. What would this mean? We’ll use 2015 figures. According to the International Diabetes Federation, there were 541,600 diabetics in Singapore that year. The total population then was 5.535 million (5,535,000).

Divide 5,535,000 by 541,600 and you’ll get 0.097850045167118.
Or,9.8 per cent of the Singapore population had diabetes in 2015. Make that 98 out of 1,000.

An 11 per cent increase in risk means 11 more people out of 1,000 could get diabetes, with each additional plate of rice that’s eaten daily. (Multiply 98 by 0.11 and you’ll get 11, rounded up.)

When you think about it, this is still quite scary. The odds aren’t great.

But if people cut down on white rice, what if they replace it with something worse?

I’m sure the Singapore Health Promotion Board thought about this long and hard.

Can switching white rice with brown really reduce the risk of diabetes? The experts seem to think so.

It’s worth noting the second study’s limitations, however: Firstly, it was conducted on Americans. And, as noted in the press release, “because brown rice consumption was low in the study population, the researchers could not determine whether brown rice intake at much higher levels was associated with a further reduction in diabetes risk.

“Substitution of other whole grains for white rice was more strongly associated with lowering diabetes risk. This observation, said the researchers, may result from more reliable estimates based on participants’ higher consumption of whole grains other than brown rice.” [direct quote from release]

Not mentioned in the ST report is the fact that the study also found that replacing white rice with other whole grains, such as whole wheat and barley, was associated with a 36 per cent reduced risk of type 2 diabetes.

So should we consider whole wheat and barley as even better alternatives to rice? Maybe.

It’d be nice to see Singapore-based research on this.

The talk about grain substitution is really just the tip of the iceberg too, in my humble opinion.

It’s time to look at just how much we are (over)eating in total. We need to re-evaluate the proportion of carbohydrates to other macronutrients, like protein, fat and dietary fibre, in our food intake.

We should also try to understand glycaemic index and glycaemic load better. And question what kinds of sugar in the carbohydrate family are, in fact, the worst.

So don’t go thinking that you can skip a bowl of rice and drink two cans of soda instead. That’s really not the point.

PS. This first blog post turned out a tad serious and science-y.  I will write about lighter stuff, so do check back.  🙂

Note: An earlier version of this article used 2013 population figures. I’ve updated it with 2015 numbers on May 11. Also, I received feedback on May 28 that I should highlight that the relative risk of 1.11 refers to the reference group used in the Harvard study. I’ve now indicated that my working shows hypothetical numbers, if the relative risk were to apply in the context of Singapore.

Photo of rice and noodles: Condesign