A study of almost 30,000 people found those who regularly consumed the fruit were a third less likely to be overweight.
They weighed more than half-a-stone (7.5lbs) less on average, had a waist that was more than an inch slimmer and a BMI (body mass index) that was one unit lower.
Dr Carol O’Neil, of Louisiana State University, and colleagues said avocados may be associated with an overall better diet and higher consumption of essential nutrients.
She said: “Avocado consumption was associated with better dietary measures and weight parameters than seen in non-consumers; consumption should be encouraged as part of an overall healthy lifestyle.”
The fruit is rich in vitamins, minerals, healthy fats and fibre - making people feel full for longer.
Unlike other fruits 77 per cent of their calories come from fat but these are mostly oleic acid - a monounsaturated fat found in olive oil.
This is the staple food of the Mediterranean diet which has been shown to decrease inflammation and lower the risk of heart disease.
In the study of 29,684 adults aged 19 and over avocado eaters had higher intakes of fibre, good fats. vitamins E and C, folate, magnesium, copper and potassium.
They also had lower consumption of carbohydrates, added sugars and salt compared to those who didn’t eat the fruit.
There was significantly reduced incidence of metabolic syndrome - a combination of high blood pressure, obesity and diabetes.
The avocado group also had lower levels of a chemical called homocysteine that can be a sign of hardening of the arteries, blood clots and other forms of cardiovascular disease.
Dr O’Neil said: “Avocado consumption was associated with higher consumption of fruit and vegetables.
“This is noteworthy, since consumption of fruit and vegetables is important for primary prevention of cardiovascular disease.
“These findings suggest a role for avocados in improving nutrient intakes and may be a strategy for getting Americans closer to meeting the fruit and vegetable
The study funded by the Hass Avocado Board and published in the journal Internal Medicine Review said a healthy intake was about half a medium avocado a day.
Nikki Ford, Hass Avocado Board director of nutrition, said: “These findings indicate incorporating avocados could be one way for Americans to meet the recommended fruit and vegetable intake and potentially improve physiologic measures.
“As we fund additional clinical studies investigating the relationship between fresh avocado consumption and weight management and risk factors for cardiovascular disease and diabetes, we continue to encourage healthcare professionals to remain committed to recommending avocados as part of an overall healthy diet.”
In recent years the avocado has become popular among the health conscious and often referred to as a superfood.
It can weigh anywhere from 8 ounces (220 grams) to 3 pounds (1.4 kg).
It is often called ‘alligator pear’ - because it tends to be shaped like a pear and have green, bumpy skin like an alligator.
Since they were first introduced to the UK over 40 years ago avocados have become a staple of the British diet eating more than 35 million each year.
Multiple scientific studies have linked avocados with health benefits ranging from anti-ageing to warding off heart disease and even cancer.