Eating More Complex Carbs, Dietary Fiber Could Help You Live Longer

• A new study builds on evidence supporting the effects of complex carbohydrate consumption on long-term health and longevity.
• The findings show that women who reported higher intakes of complex carbohydrates and dietary fiber had up to a 37% greater chance of living longer, healthier lives.
• Other factors for long-term health should be considered aside from diet, such as getting enough exercise and quality sleep.

Dietary fiber and high quality carbohydrate intake during midlife were linked to healthy aging outcomes in women later in life.

Researchers from the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University and Harvard T.H. Chan School of Public Health examined total carbohydrate intake in more than 47,000 females ages 70–93 from the Nurses’ Health Study, the largest investigation into risk factors for major chronic diseases in women.

Healthy aging was defined as healthy cognitive and physical function, good mental health, and the absence of 11 chronic conditions. A total of 3,706 participants met these criteria.

Self-reported food-frequency questionnaires were collected every four years between 1984 and 2016. Researchers examined intakes of total carbohydrates, including refined carbohydrates, high quality or unrefined carbohydrates (i.e., whole grains, fruits, vegetables, legumes), and dietary fiber. Dietary glycemic index (GI) and glycemic load (GL) were calculated based on the questionnaires.

The analysis showed that consumption of high quality complex carbohydrates and dietary fiber during midlife was linked to a 6–37% greater chance of healthy aging and improved physical and mental health.

“We’ve all heard that different carbohydrates can affect health differently, whether for weight, energy, or blood sugar levels. But rather than just look at the immediate effects of these macronutrients, we wanted to understand what they might mean for good health 30 years later,” Andres Ardisson Korat, a scientist at the HNRCA and lead author of the study, said in a news release.

“Our findings suggest that carbohydrate quality may be an important factor in healthy aging.”

“Our results are consistent with other evidence linking consumption of fruits and vegetables, whole grains, and legumes with lower risks of chronic diseases, and now we see the association with physical and cognitive function outcomes,” senior author Qi Sun, associate professor in the departments of nutrition and epidemiology at Harvard Chan School, said in a news release.

Mir Ali, MD, board certified general surgeon, bariatric surgeon, and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, agreed the findings align with general nutrition recommendations about the benefits of complex carbohydrates. Ali wasn’t involved in the study.

“Foods that have high quality or complex carbohydrates have relatively low glycemic index and glycemic load, and in this study were found to have a favorable impact on long-term physical, mental, and cognitive health,” Ali told Healthline.

Sheryl Ross, MD, board certified OB-GYN and Women’s Health Expert at Providence Saint John’s Health Center in Santa Monica, CA, echoed Ali’s remarks. Ross was likewise not involved in the study.

“Refined carbohydrates are associated with an increased risk of chronic diseases,” Ross said.

“There is no surprise with this study’s conclusion showing high quality carbohydrates promoting healthy aging and less chronic medical conditions. The specific details of our diet have never been more front and center on how we can support our longevity and live our best lives,” she told Healthline.

Carbohydrate quality matters when it comes to healthy aging.

Complex carbohydrates are rich in fiber and promote satiety, which can help with weight management. “The powerful combination of dietary fiber and high quality carbohydrates [is] the perfect duo for healthy aging and longevity,” Ross said.

Complex carbs also contain other important nutrients, such as vitamins and minerals.

“While dietary fiber is a standout component of high quality carbohydrates, these foods also deliver a spectrum of nutrients that play a critical role in supporting long-term health and longevity,” said Michelle Routhenstein, a registered dietitian at Entirely Nourished specializing in heart disease. Routhenstein wasn’t involved in the new research.

“[Many] high quality carbohydrates contain B vitamins such as folate, B6, and thiamine, which contribute to healthy methylation and help regulate homocysteine levels — key for vascular health and proper blood clotting,” she told Healthline.

Routhenstein noted that complex carbohydrates also stimulate the production of butyrate in the gut, which may promote gut health and reduce arterial stiffness to support heart health.

Ross added that high quality carbohydrates include other important nutrients like magnesium and omega-3 fatty acids, which help promote longevity. They also help regulate blood sugar.

“Carbohydrates from whole grains, fruits, vegetables, and legumes have a low dietary glycemic index (GI) and low glycemic load (GL), which have better health consequences as it relates to chronic medical conditions. Low GI and GL create more stability in blood glucose and insulin levels, which support having more energy, better mental clarity, and cognitive functioning, and less inflammation,” Ross said.

Routhenstein shared a few sources of high quality carbohydrates:

• non-starchy vegetables (i.e., broccoli and spinach)
• fruits (i.e., berries, apples, and oranges)
• legumes (i.e., lentils, chickpeas, and black beans)
• whole grains (i.e., quinoa, oats, brown rice, and whole wheat bread)

Ross explained that refined carbohydrates, such as white bread, white pasta, white rice, or foods with added sugars, are higher on the glycemic index (GI) and glycemic load (GL) scales.

• obesity
• cardiovascular disease
• type 2 diabetes
• mood disorders
• cognitive decline
• increased inflammation

“Not all carbs are created equally,” Ross said.

On the flipside, however, not all carbs are bad for you, either.

“In an era where carbohydrates are often vilified and ultra-low-carb or ketogenic diets are widely promoted, it’s critical to reframe the conversation around nutrient adequacy,” Routhenstein said.

“Many people are navigating significant nutrient deficiencies, and this research reinforces the importance of including high quality carbohydrate sources that nourish and protect the body,” she noted.

The authors of the new study note a key limitation in their findings, since the study population comprised mainly white health professionals.

Further research is needed to determine whether these findings translate to other populations.

Author Ardisson Korat said that additional research is needed to understand the effects of dietary fiber and high quality carbs on healthy aging.

“Studies are starting to find an association between food choices in midlife and quality of life in later years. The more we can understand about healthy aging, the more science can help people live healthier for longer,” Ardisson Korat said.

Ali suggested the positive health outcomes could be linked to increased fiber intake to improve glucose control, but agreed other potential mechanisms warrant further investigation.

Additionally, the effects of complex carbohydrate intake and longevity in men should be considered, but similar health benefits may be seen in men nonetheless.

“Although this study focused specifically on women, the mechanisms by which high quality carbohydrates support health, such as reducing inflammation, enhancing gut health, regulating blood sugar, and lowering cardiovascular risk, are biologically relevant to both women and men,” Routhenstein said.

The findings of the study align closely with a heart-healthy, nutrient-dense diet, Routhenstein said.

Yet supporting health and longevity goes beyond balancing macronutrient intake, she noted, especially for women.

A long-term balanced diet should also emphasize adequate intake of lean proteins and heart-healthy fats, which maintain metabolic function and hormonal balance.

“I frequently see how these approaches can backfire, particularly when they compromise heart health, bone health, and muscle mass. Instead, we should focus on responding to the body’s evolving nutrient needs.”

Physical activity is, of course, another pillar of long-term health. Most experts recommend a combination of heart-pumping aerobic exercise and strength and agility training to maintain heart health, muscle mass, and flexibility, and to prevent falls and fractures.

Current recommendations for physical activity for adults include a minimum of 150 minutes of moderate-intensity exercise per week and two days of strength training.

Routhenstein said adults should also prioritize quality sleep, which is crucial for immune function, cognitive health, and hormonal balance, and foster strong social connections to support well-being.

“Together, these lifestyle choices create a whole-person approach and a sustainable path to aging gracefully,” Routhenstein said.