Cutting back on meat and eating more vegetables could help prevent obesity among the middle-aged and elderly, a study suggests.
While previous evidence has suggested vegan and vegetarian diets may cut the risk of becoming overweight, researchers say less extreme changes may still have benefits.
Reducing the amount of animal products and sticking to a more plant-based diet was found to be linked to lower body mass index (BMI), body fat and waist circumference among adults over 45.
The study, by researchers from Erasmuc MC Rotterdam in the Netherlands, will be presented at the European Congress on Obesity in Vienna, Austria.
Lead author Zhangling Chen said: "Our study suggests that a more plant-based and less animal-based diet beyond strict adherence to vegan or vegetarian diets may be beneficial for preventing overweight or obesity in middle-aged and elderly populations.
"In other words, eating a plant-based diet to protect against obesity does not require a radical change in diet or a total elimination of meat or animal products.
"Instead, it can be achieved in various ways, such as moderate reduction of red meat consumption or eating a few more vegetables."
The researchers studied 9,641 middle-aged and elderly adults in the Netherlands, with an average age of 62, over several years.
They developed a plant-based diet index, with participants given positive scores for eating nuts, fruits and vegetables and negative scores for consuming meat, dairy and fish.
A high score on the index, which meant better adherence to a diet high in plant-based foods and low in animal-based products, was linked with lower long-term BMI and lower body fat mass, the study found.
Participants with a 10-point score had a 0.70kg per square metre lower BMI and 0.62kg per square metre lower fat mass index than those with a score of zero.
A 10-point score could be achieved by replacing 50g of meat a day with 200g of vegetables, the researchers said.
A higher plant-based score was also associated with lower waist circumference and body fat percentage, with the link stronger in 45 to 65-year-olds than older subjects.
"This probably means that middle-aged people who eat a diet rich in fruit and vegetables get the better protection, although elderly people eating a diet rich in plant-based foods will still benefit," Ms Chen said.