A
study that used data from more than 130 countries concludes that eating more
rice might protect against obesity. After controlling for a wide range of
factors, the team found that the results remained significant. Despite this,
big questions remain.
Obesity in the Western world
and beyond is on the rise. However, some countries are not facing the same
challenge.
According to the Centers for Disease
Control and Prevention (CDC), 39.8% of
people in the United States now have obesity.
In Japan, however, the figure is
just 4.3%, say the World Health Organization (WHO).
The array of factors that could be
involved in differences such as this are dizzying — so where would one begin?
According to one group of
researchers, a good place to start might be rice.
The average food intake of someone
in the United States is very different to that of someone in any country
outside of the Western world. However, diets in some of the countries with low
obesity rates share a common staple: rice.
Researchers from Doshisha Women's
College of Liberal Arts in Kyoto, Japan, decided to take a closer look. They
recently presented their findings at the European Congress on Obesity (ECO2019) in Glasgow, United
Kingdom.
A global look at rice consumption
To investigate, the scientists took
data from 136 countries. They found that countries where people ate an average
of at least 150 grams (g) of rice per day had significantly lower rates of
obesity than countries where people ate less than the global average amount of
rice, around 14 g per day.
The researchers attempted to take
into account as many confounding variables as they could, including average
education level, smoking rates, total calories consumed, money
spent on healthcare, percentage of the population over 65, and gross domestic
product per capita.
All of these variables were significantly lower in
the countries whose residents ate the most rice; however, even after accounting
for this in their analysis, the researchers found that the positive influence
of rice over obesity persisted.
From their data, they estimate that
an increase of just one-quarter of a cup of rice per day (50 g per person)
could reduce global obesity by 1%. That equates to a change from 650 million to
643.5 million adults.
"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."
Lead researcher Prof. Tomoko Imai
When considering exactly why rice
might influence obesity rates, Prof. Imai says: "Eating rice seems to
protect against weight gain. It's possible that the fiber, nutrients, and plant
compounds found in whole grains may increase feelings of fullness and prevent
overeating."
Prof. Imai adds, "Rice is also
low in fat and has a relatively low postprandial blood glucose level, which
suppresses insulin secretion."
Significant limitations
The researchers know that
distinguishing between cause and effect is incredibly challenging when looking
at diet — especially on such a large scale.
Though they accounted for as many
confounding variables as possible, it is still likely that they did not
consider many other important factors in the analysis.
They also explain that they used
country-level data, rather than person-level data. This has several drawbacks;
for instance, certain regions of some countries might eat substantially more
rice than others. Also, obesity rates can vary within a country from region to
region.
Another concern is the use of body
mass index (BMI); although it is a standard measure that
researchers use widely, it is not a measure of overall health. The scientists
did not ascertain how many people have, for instance, an unhealthily low BMI,
which would skew the data by bringing the country's average BMI down.
It is also worth pointing out that
the researchers have not published these findings in a journal and, therefore,
they have not been through a peer-review process.
Source: MedicalNews Today
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