Eating more fruits and vegetables can lead to less weight gain, and this effect is strongest among those who are genetically predisposed to be obese, a new study has found.
The study, titled “Improving fruit and vegetable intake attenuates the genetic association with long-term weight gain,” was published in The American Journal of Clinical Nutrition.
Fruits and veggies are part of a healthy diet, but most Americans have been consuming less than the recommended amounts, particularly in recent decades. This decrease has paralleled rising obesity levels, but the data on how fruit and vegetable intake affects weight gain are not definitive or consistent.
One reason may be that diet isn’t the only factor that determines weight. Other factors, such as genetics, play a key role.
In the new study, researchers used data from two studies that collected long-term health data on adult healthcare workers of European descent in the United States: the Health Professionals Follow-Up Study for males, and the Nurses’ Health Study for females.
From these studies, the researchers extracted 20 years’ worth of data on the participants’ genetics, body mass index (BMI, a measurement of weight adjusted for height), diet, and other factors. In total, the study included data on 14,251 people (5,308 males, 8,943 females).
Individuals with cancer, diabetes, or heart disease at the beginning of the study (in 1986) were excluded from the analysis.
Using the data, the researchers developed statistical models to analyze the relationship between fruit and vegetable intake and weight gain for people who were at low, intermediate, or high risk of obesity, based on a panel of 77 genetic variants that have been associated with BMI.
Over the 20 years analyzed, a higher genetic risk for obesity was associated with having a higher BMI, and BMI tended to increase over time in people with a greater genetic risk.
In contrast, people who ate more fruits and vegetables over the course of the study tended to have less of an increase, or experience a decrease, in BMI. Interestingly, this effect was the strongest among people who were at the greatest genetic risk of being heavier — that is, compared with people with a low genetic risk for obesity, people with a high genetic risk tended to lose more weight (or gain less weight) when they ate more fruits and vegetables.
This same relationship was also found when fruits and vegetables were analyzed separately, and the correlation was strongest for berries, citrus fruits, and leafy green vegetables.
“We found consistent interactions of changes in total and separate intake of fruits and vegetables with genetic susceptibility to obesity on longitudinal changes in BMI and body weight,” the researchers said.
“Increasing intake of fruits and vegetables remarkably attenuated the genetically associated increases in BMI and body weight, and the beneficial effect of improving fruit and vegetable intake on changes in BMI and body weight was more prominent in individuals with high genetic risk,” they said.