If you want to feel more satiated, lose weight and reduce your risk for heart
disease and diabetes, the solution is a meal of mostly complex carbohydrates,
but only in the evening, new Hebrew University research says.
student Sigal Sofer randomly assigned 78 police officers to either the
experimental diet of carbohydrates at dinner and other foods during the day – or
a control weightloss diet of carbohydrates and other foods throughout the
Sixty-three participants finished the six-month
program. Those who saved their carbohydrates for a meal three hours
before bedtime did significantly better than those who ate them throughout the
The experimental diet influenced the secretion patterns – in the
evening – of hormones responsible for hunger and satiety, as well as those
associated with pre-diabetes metabolic syndrome.
The researchers examined
the experimental diet’s effect on the secretion of leptin, ghrelin and
adiponectin. Leptin is considered the satiety hormone – whose level in
the blood is usually low during the day and high at night; ghrelin is considered
the hunger hormone – whose level in the blood is usually high in the day and low
during the night; and adiponectin is considered the link between obesity,
insulin resistance and the metabolic syndrome – whose curve is low and flat in
people who suffer from obesity.
Sofer carried out the study under the
auspices of Prof. Zecharia Madar, chief Education Ministry scientist, at the
Institute of Biochemistry, Food Science and Nutrition at HU’s Robert H. Smith
Faculty of Agriculture, Food and Environment.
The study has just been
published in the Obesity Journal of the Nature Publishing Group. A
connected paper was published in Nutrition, Metabolism & Cardiovascular
Sofer told The Jerusalem Post that she got the idea from
Ramadan, during which nothing is eaten during the day, but meals made up largely
of carbohydrates are eaten after sundown for 30 days.
Madar said that
when Muslims fast during the day and eat high-carbohydrate meals in the evening,
their blood shows that the secretion curve of leptin changes.
policemen in the experiment, most of them Jewish, were put into two groups – who
did not fast – those who consumed their carbohydrates in the evening, and those
who did so at any time they chose.
Sofer said that both groups received a
balanced diet, including complex carbohydrates – whole-wheat bread, rice and
pasta – with the study group concentrating their carbs in the
The policemen observed their evening regimen at home, but spent
one day at a police facility where blood samples were taken from
The researchers found that the innovative dietary manipulation led
to changes in daylight hormonal profiles in favor of the dieters: The leptin
curve became convex during daylight hours, with a nadir in the late day; the
ghrelin curve became concave, peaking only in the evening hours; and the
adiponectin curve, considered the link among obesity, insulin resistance and the
metabolic syndrome, was elevated.
At the same time this dietary pattern
led to lower hunger scores and better anthropometric (weight, abdominal
circumference and body fat), biochemical (blood sugar, blood lipids) and
inflammatory outcomes, compared to the control group.
suggest there is an advantage in concentrating carbohydrate intake in the
evening, especially for people at risk of developing diabetes or cardiovascular
disease due to obesity. “The findings lay the basis for a more appropriate
dietary alternative for those people who have difficulty persisting in diets
over time,” said Madar. “The next step is to understand the mechanisms that led
to the results obtained.”
“It’s an evolutionary mechanism. People
in ancient times had to search for food, which wasn’t possible at night, but
today, they just go to the refrigerator,” Sofer explained.