- American researchers observed the diets of 136,432 people for approximately 24 years.
- Those who ate the most non-starchy vegetables gained an average of 6.6 fewer pounds
Eating the wrong kind of vegetables can cause you to gain weight in middle age, new research suggests.
People who eat more servings of peas, sweet corn and potatoes are more likely to gain weight than those who eat non-starchy vegetables such as broccoli, carrots and spinach.
Meanwhile, switching to high fiber consumption (such as whole grains and fruits, including apples and pears) may also reduce the effects of midlife spread, they found.
Researchers at the Harvard TH Chan School of Public Health analyzed the diets of 136,432 men and women aged 65 or younger between 1986 and 2014, for an average time of 24 years.
Participants completed questionnaires on personal characteristics, medical history, lifestyle, and other health-related factors at baseline and every 2 to 4 years thereafter.
People who eat more servings of peas, sweet corn and potatoes are more likely to gain weight than those who eat non-starchy vegetables such as broccoli, carrots and spinach. Meanwhile, switching to high fiber consumption (such as whole grains and fruits, including apples and pears) can also reduce the effects of midlife spread, scientists found.
On average, people gained 3.3 pounds (1.5 kg) every four years, which is equivalent to about 1.5 kilograms over the next two decades.
They found that increases in glycemic index and glycemic load (measures of the effects of different foods on blood sugar levels) were strongly related to weight gain.
For example, a 100 g/day increase in added starch or sugar was associated with a weight gain of 3.3 pounds and 1.9 pounds over four years, respectively.
Those who ate the most non-starchy vegetables, such as broccoli, carrots and spinach, gained an average of 6.6 pounds less, while those who ate potatoes and corn could expect to gain 5.7 pounds more over the same period.
An increase of 10 grams of fiber per day was linked to a weight loss of 1.7 pounds on average, according to findings published in the BMJ.
The associations were stronger among participants with excessive body weight than among those with normal weight. Most of these associations were also stronger among women.
In additional analyses, the researchers found that replacing carbohydrates from refined grains, starchy vegetables, and sugary drinks with equal servings of carbohydrates from whole grains, fruits, and non-starchy vegetables was associated with less weight gain.
The authors note that this is an observational study, so they cannot establish cause, with limitations such as reliance on self-reported estimates of both carbohydrate intake and weight outcomes.
However, they say their findings “highlight the potential importance of carbohydrate quality and source for long-term weight management, especially in people with excessive body weight.”
WHAT SHOULD A BALANCED DIET LOOK LIKE?
Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains, according to the NHS.
• Eat at least five servings of a variety of fruits and vegetables every day. All fresh, frozen, dried, and canned fruits and vegetables count
• Base meals are based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains.
• 30 grams of fiber per day: This is equivalent to eating all of the following: five servings of fruits and vegetables, two whole-grain crackers, two thick slices of whole-wheat bread, and one large baked potato with skin.
• Eat some dairy or dairy alternatives (such as soy drinks), choosing options low in fat and sugar.
• Eat some beans, legumes, fish, eggs, meat and other proteins (including two servings of fish each week, one of which should be fatty).
• Choose unsaturated oils and spreads and consume them in small quantities
• Drink six to eight cups/glasses of water a day
• Adults should consume less than 6 g of salt and 20 g of saturated fat for women or 30 g for men per day.
Source: NHS Eatwell Guide