Vegan diet beats Mediterranean diet when it comes to jump-starting weight loss, scientists find

Independent

27-06-2025

Switching to a vegan diet can help promote weight loss by reducing inflammation, a new study suggests.
Scientists compared a plant-based diet with a so-called 'Mediterranean diet' – one that includes moderate amounts of fish, poultry, dairy and eggs – and found that eliminating these altogether resulted in a net reduction in the body's production of acid.
Researchers in the four-month study, which has been published in the journal Frontiers in Nutrition, found that switching to a low-fat vegan diet could slash the body's overall acidity, a change that was associated with weight loss.
"Eating acid-producing foods like meat, eggs, and dairy can increase the dietary acid load, or the amount of acids consumed, causing inflammation linked to weight gain," said Hana Kahleova, a co-author of the study.
"But replacing animal products with plant-based foods like leafy greens, berries, and legumes can help promote weight loss and create a healthy gut microbiome,' Dr Kahleova explained.
In the study, 62 overweight adults were randomised to follow either a Mediterranean or a low-fat vegan diet for 16 weeks, separated by a four-week cleansing period, followed by an additional 16 weeks on the alternate diet.
Researchers closely monitored participants' dietary records to calculate their acid load – a measure of the net acid production in the body from the foods we eat.
For instance, scientists say food like meat, fish, eggs, and cheese causes the body to produce more acid, a change linked to chronic inflammation and that can lead to increased body weight.
In comparison, they say plant-based diets are more alkaline and are associated with weight loss, improved insulin sensitivity, and lower blood pressure.
Researchers found that the acid load significantly decreased under a vegan diet, with no significant change on the Mediterranean diet.
This reduction, scientists say, is associated with significant weight loss, which remained even after adjusting for changes in calorie intake.
Participants in the study experienced weight loss by up to 5 kg (13 lbs) on the vegan diet, compared with no change on the Mediterranean diet.
Scientists recommend more consumption of alkalising food such as leafy greens, broccoli, beets, asparagus, garlic, carrots, and cabbage, as well as fruits like berries, apples, cherries, apricots, or cantaloupe.
Legumes like lentils, chickpeas, peas, beans, or soy and grains like quinoa or millet can also have an alkalising effect, they say.
'The alkalising effect of a vegan diet may be an independent mechanism by which a vegan diet promotes weight loss,' researchers concluded.