New research following more than 47,000 women suggests that the quality of the carbohydrates you eat in midlife may help shape how well you age.
Carbohydrates have spent decades being cast as the nutritional villain. Bread gets blamed for weight gain. Pasta gets swapped for protein. Potatoes disappear from dinner plates. And “cut the carbs” has become shorthand for eating healthier.
But carbohydrates aren't one thing. A long-running study offers a useful reminder that where your carbs come from may matter far more than simply eating fewer of them.
Carb quality — not carb quantity — tracked with healthy aging across three decades. Whole grains, fruit, vegetables and legumes were associated with better outcomes; refined grains and added sugars with worse ones. Fiber may explain much of the effect.
The study
Chapter 01 · JAMA Network Open, 2025
In a 2025 study published in JAMA Network Open, researchers examined the diets of 47,513 women in the Nurses' Health Study and followed their health for more than three decades. They wanted to know whether the kinds of carbohydrates women ate in midlife were associated with how healthy they were in their 70s, 80s, and early 90s.
The finding was striking: women who consumed more high-quality carbohydrates from whole grains, fruits, vegetables, and legumes had greater odds of what researchers called healthy aging — and healthy aging meant considerably more than simply living longer. Researchers looked for women who reached older adulthood without 11 major chronic diseases, physical limitations, memory problems, or poor mental health.
The women were an average of about 48 years old when researchers began assessing their diets in the mid-1980s. Their health was evaluated decades later, when participants were between 70 and 93.
Keep in mind: the study was observational, which means it can identify associations but cannot prove that eating a particular kind of carbohydrate caused someone to age better. And a 31% increase in odds does not mean someone becomes 31% healthier.
Still, the larger pattern was consistent. Carbohydrates from fruits, vegetables, whole grains, and legumes were associated with better aging outcomes. Dietary fiber was, too. Diets with a higher glycemic index and a higher ratio of carbohydrate to fiber were associated with poorer outcomes.
Carbohydrates aren't automatically healthy or unhealthy. Their source matters.
What Makes a Carb “High Quality”?
Chapter 02 · The package, not the macro
Picture two breakfasts. One is a bowl of oatmeal topped with berries and walnuts. The other is a frosted pastry. Both contain carbohydrates — your body can break both down into glucose. But nutritionally, they're very different packages.
Whole carbohydrate foods tend to arrive with other things your body can use: fiber, vitamins, minerals, plant compounds, and intact food structures that influence how quickly they're digested. Highly refined carbohydrates have often had much of that structure — and particularly fiber — removed during processing.
In this study, researchers classified carbohydrates from whole grains, fruits, non-starchy vegetables, and legumes as high quality. Refined grains and added sugars were among the lower-quality sources they examined.
Fiber May Be the Quiet Star
Chapter 03 · One nutrient kept reappearing
One nutrient kept showing up throughout the research: fiber. Women who consumed more total dietary fiber in midlife had greater odds of healthy aging decades later. Fiber from fruits, vegetables, and cereal grains was also associated with better outcomes.
When researchers statistically accounted for fiber, some of the associations between carbohydrate intake and healthy aging became weaker. That suggests fiber may explain at least part of the relationship — and it would make biological sense.
Fiber does much more than keep digestion regular. Certain types can slow digestion and moderate the rise in blood sugar after eating. Soluble fiber can help lower LDL cholesterol. Other fibers reach the colon, where gut microbes ferment them and produce compounds that help support the intestinal environment. And unlike many headline-grabbing nutrients, fiber is abundant in remarkably ordinary foods.
5 Carbohydrate Sources Worth Eating More Often
Chapter 04 · Where to start
The study wasn't designed to crown individual foods as longevity champions. Instead, it identified broader carbohydrate categories associated with healthier aging. Within those categories, these are useful places to start.
What About Glycemic Index?
Chapter 05 · A number with limits
You've probably encountered the term glycemic index, or GI. It describes how quickly carbohydrate-containing foods raise blood glucose compared with a reference food. In this study, diets with a higher overall glycemic index were associated with lower odds of healthy aging, and a higher carbohydrate-to-fiber ratio with poorer outcomes.
But that doesn't mean you need to memorize the glycemic index of everything in your pantry. Meals are complicated. We rarely eat one carbohydrate in isolation, and protein, fat, fiber, preparation method, portion size, and the other foods on your plate can all influence the blood-sugar response.
Don't Obsess Over the Carb-to-Fiber Ratio
Chapter 06 · Quality, restated
Researchers also examined the ratio of total carbohydrate to fiber in participants' diets. Women in the highest carbohydrate-to-fiber group had lower odds of healthy aging compared with those in the lowest group — another way to think about quality: not simply how many carbohydrates you're eating, but how much fiber accompanies them.
You should know: you may encounter advice recommending specific ratios, such as 10 grams of carbohydrate for every gram of fiber. That can be a useful shorthand, but this study does not establish a universal 10:1 target. The broader lesson is easier: choose carbohydrates that bring fiber with them.
What This Study Can't Tell Us
Chapter 07 · Limits of the evidence
The study included female nurses, most of whom were White, so its findings may not apply equally to every population. Diet was self-reported through food-frequency questionnaires — useful for large groups over long periods, but not perfectly precise.
Because this was observational, researchers cannot conclude that high-quality carbohydrates themselves caused healthier aging. People who eat more fruits, vegetables, whole grains, and legumes may differ from people who don't in other important ways. The researchers adjusted for physical activity, smoking, body mass index, and other aspects of diet — but no statistical model can eliminate every possible difference between people.
So the finding shouldn't become eat lentils and you'll live to 90. A more accurate conclusion: the quality of the carbohydrates you eat in midlife may be one meaningful part of how well you age. That's less dramatic. It's also much more useful.
Bottom Line
Chapter 08 · What to take away
Carbohydrates aren't the enemy of healthy aging. Women who ate more carbohydrates from whole grains, fruits, vegetables, and legumes — and more dietary fiber overall — in midlife were more likely to reach older adulthood in good physical, cognitive, and mental health. Refined carbohydrates were associated with lower odds of doing so.
That doesn't prove eating more high-quality carbohydrates will make you live longer or prevent disease. But it adds to a much larger body of nutrition research pointing in a familiar direction: eat more plants, choose whole foods more often, and get enough fiber — and worry a little less about whether something technically counts as a carb.
Because when it comes to carbohydrates, the better question isn't should I eat them? It's: what are they bringing with them?
Ardisson Korat AV, Duscova E, Shea MK, et al. “Dietary Carbohydrate Intake, Carbohydrate Quality, and Healthy Aging in Women.” JAMA Network Open. 2025;8(5):e2511056.
The All Healthy editorial team reads the research so you don't have to.
A NASM certified nutrition coach and web editor at All Healthy. She digs through the research on nutrition, fitness and supplements, then turns it into expert-backed advice you can actually use.
