It’s often thought that eating high-carbohydrate foods such as bread, rice, potatoes – even chickpeas and fruit – causes weight gain.
Cutting carbs has long been a popular approach for preventing or losing unwanted pounds.
In addition to consuming fewer calories, though, research suggests that low-carbohydrate dieters are more likely to miss out on certain nutrients, including vitamin C, magnesium, folate and iron.
There’s another downside to skimping on carbohydrates.
According to researchers from Tufts University in Boston, doing so can shorten your healthspan, the number of years you live in good health.
Here’s an overview of the new study, plus tasty ways to add healthy high-carb foods to your regular diet.
Beyond bread and pasta – carbohydrates defined
The carbohydrate family includes simple sugars, starches and fibre. Simple sugars include fructose (in fruit, sweet vegetables, honey), sucrose (in fruit, table sugar, maple syrup) and lactose (in milk, yogurt, cheese).
Starches, also called complex carbohydrates, are long chains of hundreds or thousands of glucose units – the simplest form of carbohydrate – linked together. Bread, rice, pasta, sweet potato, quinoa and oats are examples of starchy foods.
Dietary fibre is a type of carbohydrate that the body can’t break down or absorb. Fibre passes through the intestinal tract undigested.
The carbohydrate-healthy longevity link
The new research, published May 16 in the journal JAMA Network Open, investigated the relationship between carbohydrate intake and healthy aging using data collected over three decades from the continuing U.S. Nurses’ Health Study.
Participants were 47,513 healthy women with an average age of 48 at the beginning of the study. Demographic, lifestyle and health information were collected every two years during the study period.
Healthy aging was defined as reaching age 70 free of 11 major chronic diseases – such as hypertension, heart disease, cancer and diabetes – and without impairment in cognitive function, physical function or mental health.
After 32 years of follow up, only 7.8 per cent of participants met the definition of healthy aging.
Women whose diets were the highest in total carbohydrates (55 per cent of daily calories) during midlife (early 40s to early 60s) – versus the least (38 per cent of daily calories) – were 29 per cent more likely to age healthfully.
Conversely, participants with the highest intake of refined carbohydrates (defined as carbohydrates from refined grains, added sugars and white potatoes due to their high glycemic index) were 15 per cent less likely to achieve healthy aging compared with those with the lowest intake.
When the researchers looked specifically at high-quality carbohydrates – carbohydrates from whole fruit, vegetables, whole grains and pulses (beans, lentils) – participants who consumed the most (21 per cent of daily calories) had a 50 per cent greater chance of achieving healthy aging compared with those who consumed the least (7 per cent of daily calories).
Greater intakes of carbohydrates from whole fruit, vegetables and whole grains were each associated with healthy aging.
Intakes of total fibre, as well as fibre from fruits, vegetables and cereal grains, were also linked to living longer in good health.
These results remained unchanged after accounting for age, body mass index and overall diet quality.
This was a prospective observational study and, as such, it doesn’t prove a direct cause and effect relationship.
Protective effects of healthy carbohydrates
Even so, the findings are consistent with previous studies linking specific carbohydrate foods, as well fibre from fruit and cereal, to a lower risk of chronic disease and premature death.
Fibre in high-quality carbohydrate foods may help protect against cardiovascular disease and early death by promoting a diverse and healthy gut microbiome.
A high-fibre diet is also associated with lower levels of chronic, low-grade inflammation, a hallmark of aging.
Anti-inflammatory polyphenols and B vitamins, especially B12 and folate, found in many high-quality carbohydrates may also play a role in healthy aging.
Ways to add high-fibre carbohydrate foods to your spring and summer diet
Use cooked whole grains as a base for a grain salad. Toss with olive oil, lemon juice, diced cucumber and red onion, toasted nuts, feta and chopped fresh parsley and mint.
Try cooked farro (10 g fibre per one cup), sorghum (10 g per cup), bulgur (8 g per cup), barley (8 g per cup), buckwheat (4.5 g per cup) or quinoa (5 g per cup).
Add fibre-packed pulses to grain and leafy salads or make a mixed bean, lentil or chickpea salad. Try homemade black bean burgers. Depending in the type, pulses serve up 12 to 16 g of fibre per cup.
Eat whole fruit every day. Higher fibre choices include raspberries, blackberries, blueberries, kiwifruit, apples, pears and cherries.
Include nutrient-dense sweet and starchy vegetables in your menu, too.
Add grilled sweet potato or butternut squash slices to a grilled vegetable platter. Toss fresh green peas into salads and pastas or add to a frittata. Make a roasted beet salad with orange slices, walnuts and feta or goat cheese.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD
