- A whole grain has the
bran, the germ, and the endosperm in same proportions as of the grain while
growing in the ﬁelds.
- The effects of a whole-grain diet on resting
metabolic rate were sensitive to dietary adherence.
- A combination of increased resting metabolic rate and greater fecal
losses help to lose extra 100 calories per day.
whole grains for refined grains in the diet increases the loss of calories.
Whole grains retain calories during digestion and helps in speeding up the
possess numerous health benefits and
epidemiological studies have suggested that whole grains improve glycemic
control and insulin sensitivity.
‘A diet rich in whole grains not only helps in improving digestion but also helps in increasing the resting metabolic rate, an effect that is similar to exercise.’
there has been a controversy whether whole grains and fiber are beneficial for
weight regulation, as there hasn't been any data available from controlled
this new study, food was provided to participants for eight weeks which helps
in explaining how whole grain consumption is beneficial in weight management.
The study was done to examine levels of hunger, satiety and the effect of whole
grains on resting metabolic rate and fecal energy losses and to compare it with
previous studies have suggested benefits of whole grains and dietary fiber on
chronic disease risk. This study helps to quantify how whole grains and fiber
work to benefit weight management and lend credibility to previously reported
associations between increased whole grains and fiber consumption, lower body
weight and better health," says Phil J. Karl, PhD, first author of the
study,nutrition scientist at the U.S. Army Research Institute of Environmental
Medicine in Natick, MA.
grain vs. Refined grains
A whole grain has the bran, the germ,
and the endosperm. The outer nutritious layer has the same proportions as when
the grain was growing in the ﬁelds. Whole-wheat, oatmeal, brown rice, barley, rice, sorghum, quinoa, rye,
buckwheat, millets, amaranth are some of the widely used whole grains. They are high in carbohydrates & protein,
low in fats and provide varying amounts of fiber, B vitamins and minerals like
magnesium, selenium and copper.
on the other hand, are starches that have
been processed and are broken down into fine textured particles. Whole grains
undergo milling and the nutrient-rich bran and germ are removed while
processing. The starch of dietary fiber, iron and many forms of B vitamin are
drained. Though other nutrients like iron, folate can be enriched, fiber is
was the study done?
men and women between the ages of 40 and 65 were randomized to either the whole
grain diet group or the refined grain diet group. The study was conducted for 8
calorie needs of the participants were determined. For the first two weeks of
the study, all the participants ate the same type of food. After which the
participants were randomly assigned to either whole grains or refined grains
difference between the groups was mostly the grain and fiber content, while the
energy, macronutrient composition, type of food and meal structure were
were asked to consume all the food that was provided, to return the food they
had not eaten and their physical activity pattern remained unchanged.
Researchers measured body weight, metabolic rate, blood glucose, fecal
calories, hunger and fullness throughout 8 weeks.
was the effect?
who ate a diet with whole grains, nearly matched the daily recommended dietary
allowance(RDA) for fiber. Compared to people who ate refined grains without
much fiber, they lost an extra 100 calories per day due to the combination of
increased resting metabolic rate and greater fecal losses.
provided all food to ensure that the composition of the diets differed only in
grain source. The extra calories lost by those who ate whole grains was
equivalent of a brisk 30 min walk - or enjoying an extra small cookie every day
in terms of its impact," said senior author Susan B. Roberts, Ph.D.,
senior scientist and director of the Energy Metabolism Laboratory at USDA
much fiber do we need?
- At the end of 8 weeks, those who
ate whole grains had an increase in resting metabolic rate and fecal energy
losses compared to those who ate refined grains.
- The extra
fecal energy losses were due to the effect of fiber in the digestion of other
foods and not due to the extra fiber itself.
- The effects
of a whole-grain diet on resting metabolic rate was sensitive to dietary
adherence. Resting metabolic rate is the speed at which the organs function at
- Commercially available whole grain flour products
were used in the study. These foods with the kernels of whole grain might
elicit more pronounced benefit.
- Hunger, fullness and diet
satisfaction were not statistically different between the diets.
recommended dietary allowance of whole grains for women is a minimum of three
ounces and four ounces for men. This is equivalent to consuming 1½ to 2 cups of
brown rice or oatmeal each day.
to the numerous health
benefits of dietary fiber
recommends Americans to replace refined grains with whole grains.
- What's a Whole Grain? A Refined Grain? -