Increasing
Daily Nut Consumption May Help Stave Off Gradual Weight Gain, Reduce Obesity
Risk
By Sci-News Staff / Source
Nuts are nutrient-dense foods rich
in unsaturated fatty acids, vitamins, minerals and fiber. Their high fat content
leads some to perceive nuts as unhealthful and to be avoided by those
attempting to manage or lose their body weight.
Consumption of nuts and seeds in the
U.S. increased from 0.5 servings/day in 1999 to 0.75 servings/day in 2012.
A research team led by Dr. Deirdre
Tobias of the Harvard University T.H. Chan School of Public Health aimed to
evaluate the association between changes in total consumption of nuts and
intakes of different nuts (including peanuts) and long-term weight change, in
three independent cohort studies.
They analysed information on weight, diet and physical activity in 51,529 male health professionals (40-75 years old) from the Health Professionals Follow Up Study; 121,700 nurses (35-55 years old) from the Nurses Health Study (NHS); and 116,686 nurses (24-44 years old) from the Nurses Health Study II (NHS II).
Over more than 20 years of
monitoring, participants were asked every 4 years to state their weight, and
how often, over the preceding year they had eaten a serving (28 g) of nuts,
including peanuts and peanut butter.
Average weekly exercise — walking, jogging, cycling, swimming, racquet sports and gardening — was assessed every two years by questionnaire. It was measured in metabolic equivalent of task hours, which express how much energy (calories) is expended per hour of physical activity.
Average annual weight gain across
all three groups was 0.32 kg.
Between 1986 and 2010, total nut
consumption rose from a quarter to just under half a serving/day in men; and
from 0.15 to 0.31 servings/day among the women in the NHS study.
Between 1991 and 2011 total daily
nut consumption rose from 0.07 to 0.31 servings among women in the NHS II
study.
Increasing consumption of any type
of nut was associated with less long-term weight gain and a lower risk of
becoming obese (BMI of 30 or more kg/m2), overall.
Increasing nut consumption by half a
serving a day was associated with a lower risk of putting on 2 kg or more over
any 4 year period. And a daily half serving increase in walnut consumption was
associated with a 15% lower risk of obesity.
Substituting processed meats,
refined grains, or desserts, including chocolates, pastries, pies and donuts,
for half a serving of nuts was associated with staving off weight gain of between
0.41 and 0.70 kg in any 4 year period.
Within any 4 year period, upping
daily nut consumption from none to at least half a serving was associated with
staving off 0.74 kg in weight, a lower risk of moderate weight gain, and a 16%
lower risk of obesity, compared with not eating any nuts.
And a consistently higher nut intake
of at least half a serving a day was associated with a 23% lower risk of
putting on 5 kg or more and of becoming obese over the same timeframe. No such
associations were observed for increases in peanut butter intake.
“Our findings support food-based
dietary recommendations and support the incorporation of nuts as an effective
strategy for making attainable dietary modifications for the primary prevention
of obesity,” Dr. Tobias and colleagues said.
