Which fruits and veggies are most fattening?
An extra serving of certain fruits and vegetables each day for four years can cause weight gain or weight loss. But which foods cause the most?
If you are struggling with an expanding waistline, you may want to add blueberries and pears to your grocery shopping list and leave out potatoes, corn and peas.
Researchers from Harvard University have found while eating more fruit and vegetables can prevent long-term weight gain, specific types can either enhance or curb weight loss efforts.
In a study involving more than 133,000 adults in the United States, they found those who ate an extra handful of blueberries each day lost more than half a kilogram over a four-year period.
Starchy vegetables, including potatoes, peas and corn, won’t help you on your weight loss journey. Photo: Edwina Pickles
The other fruits most strongly linked with weight loss were apples, pears, strawberries and grapes.
The researchers also found those who ate an extra serving of corn a day gained nearly a kilogram over a four-year period.
Other starchy vegetables such as peas and potatoes also had a similar impact on weight. Increased intake of non-starchy vegetables such as beans and broccoli helped participants keep their waists trim.
Increased intake of potatoes, peas and corn are strongly linked with weight gain. Photo: PLOS Medicine
“The benefits of increased consumption were greater for fruits than for vegetables and strongest for berries, apples/pears, tofu/soy, cauliflower, and cruciferous and green leafy vegetables,” wrote lead author Monica Bertoia from Harvard’s School of Public Health in the latest PLOS Medicine.
“Increased satiety with fewer calories could be partly responsible for the beneficial effects of increasing fruit and vegetable intake.”
The study was based on responses to dietary questionnaires and self-reported weight changes by more than 133,000 adults in the United States every four years between 1986 and 2010.
Nutritionist Rosemary Stanton. Photo: Steve Baccon
The researchers took into account lifestyle variables such as smoking status, physical activity and diet.
They found that in a four-year period, participants who ate an extra daily serving of fruit shed 0.24 kilograms, and an extra daily serving of vegetables, 0.11 kilograms.
“We found that many vegetables were inversely associated with weight change, but starchy vegetables such as peas, potatoes, and corn had the opposite association in which increased intake was associated with weight gain,” wrote Ms Bertoia.
Blueberries, apples and cauliflower are at the top of the list of the most diet-friendly fruits and vegetables. Photo: PLOS Medicine
“Although these vegetables have nutritional value (potassium, vitamin C, vitamin B6, iron, fibre, and protein), they have a higher glycaemic load (lower carbohydrate quality) that could explain their positive association with weight change.”
Nutritionist Rosemary Stanton told Fairfax Media the inverse association finding for general fruit and vegetable consumption looked fine and was in harmony with other similar studies.
But she noted the confidence intervals – the range of values for consumption – for peas and corn were statistically problematic.
“For potatoes, few people eat straight steamed or boiled potatoes so potatoes are usually accompanied by fat, including baked (added oil), boiled or mashed with butter, margarine or sour cream added,” she said.
“Also, some people only eat peas and potatoes so those people may have lower overall vegetable consumption.”
More than 90 per cent of Australian adults do not eat the recommended five serves of vegetables a day, and half do not eat the recommended two serves of fruit, according to the Australian Institute of Health and Welfare’s health report.
“While adult Australians aged 25 to 44 are generally healthy, unhealthy behaviours such as not exercising or not eating enough fruit and vegetables place them at risk of developing long-term conditions in the future,” the report said.
The study does not show cause-and-effect, but the Havard researchers hope their findings can provide further food-specific guidance to prevent obesity, a big risk factor for type 2 diabetes, heart disease, and cancers.