A large new European study finds that simply eating a lot of fruits and vegetables may not be enough to stave off the weight gain that often comes with age -- except for people who recently quit smoking.
Researchers found that of nearly 374,000 adults in 10 European countries, who were followed for five years, those who ate the most fruits and vegetables were no less likely to gain weight once other factors -- like calorie intake and exercise habits -- were taken into account.
The results, reported in the American Journal of Clinical Nutrition, are not an excuse to skip the fruits and veggies, however.
Plant foods are full of nutrients that may help ward off chronic diseases like heart disease and some cancers, note the researchers, led by Anne-Claire Vergnaud of Imperial College London in the UK.
And in some past studies that assigned overweight people to eat more fruits and vegetables, the diet change has seemed to help.
But the current findings do point to the importance of overall lifestyle in maintaining weight as one ages.
For the study, Vergnaud's team looked at diet and weight information collected from adults between 25 and 70 years old.
Over five years, the study participants gained about one pound per year, on average.
Among men, weight gain generally dipped somewhat as their fruit and vegetable intake rose. But that link disappeared when the researchers accounted for other factors, like the men's daily calories, exercise habits and education levels.
Among overweight women, those who said they ate the most vegetables tended to gain more weight over the next five years.
That, the researchers speculate, could be because some of those women were on weight-loss diets that encourage eating a lot of vegetables. Many people who go on special diets notoriously see their weight yo-yo over time.
There was one group for whom higher fruit and vegetable intake was linked to less weight gain: people who quit smoking during the study period. The reasons are not clear, Vergnaud's team says.
But they speculate that healthy eating habits may help prevent the weight gain that many smokers experience when they try to kick the habit.
If that's true, they write, "this finding may have important public health implications because weight gain after smoking cessation is a frequent reason for relapse."
In general, experts urge people to get plenty of fruits and vegetables for the good of overall health. The "DASH" diet recommended for lowering blood pressure and cholesterol suggests four to five servings of fruit and the same number of vegetable servings each day.
A half-cup of cooked vegetables or a medium-sized piece of fresh fruit would be examples of a serving.
Studies suggest that the average adult in the US gets only two or three servings of fruits and vegetables combined each day.
