New research has discovered walnuts to be one of a number of foods that can help you slim down.
They have previously been found to stave off dementia.
However, in a study published in the journal Nutrition, they revealed that a daily handful also worked to control appetite.
It’s thanks to the high amounts of polyunsaturated fats (PUFAs) which can prevent overeating.
The researchers also found that oily fish such as salmon, tuna, flax seed, fish oil supplements or canola oil – also rich in the fats – had the same effect.
This is because PUFAs dampen down a hormone that boosts hunger, while triggering the release of another that ups feelings of fullness.
Nutritionist Professor Jamie Cooper, of the University of Georgia in the US, said: “Appetite hormones play an important role in regulating how much we eat.
“These findings tell us that eating foods rich in PUFAs, like those found in walnuts, may favourably change appetite hormones so we can feel fuller for longer.”
Those who consumed a diet high in PUFAs had a significant decrease in fasting ghrelin, a hormone that increases hunger.
At the same time, there was an increase in peptide YY (PYY), a hormone that increases fullness or satiety.
PUFAs are already known to be good for health by helping reduce cholesterol and providing essential fats like omega-6 and omega-3 that the body can’t produce itself.
However, this new research shows for the first time that eating foods high in these polyunsaturated fats can prevent overeating.
The effects in the study were compared to a control diet.
It comprised of 7 per cent polyunsaturated fat, 15 per cent monounsaturated fat and 13 per cent saturated fat.
This was in contrast to the PUFA-rich diet which was 21 per cent polyunsaturated fat, 9 per cent monounsaturated fat, and 5 per cent saturated fat.