Eat more rice, cure obesity – this is the news that went around the world in the past 24 hours, largely without critical analysis. Is there a grain of truth in such a bold declaration?

Or has an interesting observation by Japanese scientists been over-cooked by hype? The secret is more likely to be in portion sizes, not the food itself.

A study from Doshisha Women’s College of Liberal Arts, Kyoto, Japan, found obesity levels are “substantially lower in countries that consume high amounts of rice” – meaning an average of 150 grams per day, per person.

Countries with an average lower rice intake – 14 grams per day – were found to have higher obesity levels.

There’s a link, but what does it really mean?

The study, presented this week at the European Congress on Obesity in Glasgow, concluded: “An extra quarter cup of rice per person per day may be enough to lower worldwide obesity levels by 1 per cent.”

The researchers analysed data from the UN Food and Agriculture Organisation. This included relative consumption (grams of rice per day per person) and energy consumption (kilo calories per day per person) in the diets of 136 countries, which were eventually categorised into low and high (rice) consumption groups.

Also factored were estimates of obesity prevalence, average number of years spent in education, percentage of population over 65 years old, gross domestic product (GDP) per capita, and health expenditure.

Poorer countries eat the most rice

Bangladesh ranked first at 473 grams per day per person (3.3 per cent of the population obese); Laos was second with 443 grams per day (3 per cent obese); Cambodia third with 438 grams per day (2.9 per cent obese). These countries also had lower consumption of energy.

At the other end of the scale, where obesity is in plague proportions: Australia was 67th with 32 grams per day and two thirds of adults overweight or obese; the US 87th with 19 grams per day and one in three adults obese); France was 99th with 15 grams per day, and about one in four adults are obese.

The college’s Professor Tomoko Imai, who led the research, interpreted the numbers this way: “Eating rice seems to protect against weight gain. It’s possible that the fibre, nutrients, and plant compounds found in whole grains may increase feelings of fullness and prevent overeating.”

Professor Lynn Riddell is Associate Dean in the Faculty of Health at Deakin University.

“The reason why these countries have typically lower obesity is that their overall energy intake is compromised,” Dr Riddell told The New Daily.

“You have high levels of wasting and stunting in child populations … and overall an energy deficit traditionally in those countries.”

Not just any rice

Another problem with the study: the researchers used “rice” as an umbrella term for brown or unrefined rice, white rice and highly refined rice flour. The more refined the grain, the less fibre and micronutrients.

Dr Riddell advised there was no reason to choose rice over any other grain – or any one food – as protection against obesity. She did advise people who chose to eat grain to opt for whole grain, as research showed it was conducive to lower body weight.

Dr Gunter Kuhnle, Associate Professor in Nutrition and Health, University of Reading, posted similar comments in his response to the study at the Science Media Centre: “White rice consists mainly of carbohydrates, and there is no reason to assume that carbohydrates from rice – and not other sources such as grains or potatoes – have a different effect on obesity.”

Japan, not so grainy

Finally, there is a contradiction in Professor Imai’s final recommendation: “The observed associations suggest that the obesity rate is low in countries that eat rice as a staple food. Therefore, a Japanese food or an Asian-food-style diet based on rice may help prevent obesity.”

There is a big difference between a heart-friendly Japanese diet and sugar-rich Thai food or ghee-based curries.

And the Japanese diet isn’t overly rice heavy.

According to 2015 figures, Japan ranked 50 with 119 grams per person per day being eaten. It enjoys the lowest obesity rate (3.7 per cent) for the developed world. Smaller portions might be helping.

The New Daily wasn’t able to read the study paper, which hasn’t been published – and has relied on a statement from the European Association for the Study of Obesity.