1217 GMT January 20, 2020
Substituting unhealthy foods, such as processed meats, French fries, and crisps (potato chips) with a half a serving of nuts may be a simple strategy to ward off the gradual weight gain that often accompanies the aging process, suggested the researchers, medicalxpress.com wrote.
On average, US adults pile on 1lb or nearly half a kilo every year. Gaining 2.5-10 kilos in weight is linked to a significantly greater risk of heart disease/stroke and diabetes.
Nuts are rich in healthy unsaturated fats, vitamins, minerals and fiber, but they are calorie dense, so often not thought of as good for weight control. But emerging evidence suggests that the quality of what's eaten may be as important as the quantity.
Amid modest increases in average nut consumption in the US over the past two decades, the researchers wanted to find out if these changes might affect weight control.
They analyzed information on weight, diet and physical activity in three groups of people: 51,529 male health professionals, aged 40 to 75 when enrolled in the Health Professionals Follow Up Study; 121,700 nurses, aged 35 to 55 when recruited to the Nurses Health Study (NHS); and 116,686 nurses, aged 24 to 44 when enrolled in the Nurses Health Study II (NHS II).
Over more than 20 years of monitoring, participants were asked every four years to state their weight, and how often, over the preceding year they had eaten a serving (28 g or 1 oz) 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 (MET) 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 (0.71 lb). 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 two or more kilos over any four year period. And a daily half serving increase in walnut consumption was associated with a 15 percent 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 four year period.
Within any four 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 percent 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 percent lower risk of putting on five or more kilos and of becoming obese over the same timeframe.
No such associations were observed for increases in peanut butter intake.
The findings held true after taking account of changes in diet and lifestyle, such as exercise and alcohol intake.