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by Reed Mangels, PhD, RD

In some circles, carbohydrates are viewed negatively – “Eat more protein,” “Avoid grains – eat a Paleo Diet.” This is an over simplification. When we think about carbs, it may be important to divide them into two groups, refined/processed and unrefined/unprocessed. Refined carbohydrates account for over 80% of the carbohydrates that Americans eat. Refined carbohydrates include refined grains like white bread and white rice, and sugar or other caloric sweeteners added to foods. Unrefined carbohydrates are found in whole grains, whole grains breads, fruits, vegetables, and legumes and account for about 20% of the carbohydrates Americans eat.

A recent study (1) examined the long-term effects of eating different kinds of carbohydrates in midlife on healthy aging in women. Healthy aging was defined as not having major chronic diseases, not being impaired physically or mentally, and having good mental health.

What is the study?

The study subjects were 47,513 women who participated in a large, long-term study called the Nurses’ Health Study and who were younger than 60 years in 1984. The women completed questionnaires about their eating habits in 1984 and 1986 and then were followed for 32 years. Based on the questionnaires, the researchers estimated the women’s total carbohydrate intake, high-quality carbohydrate intake, and refined carbohydrate intake. High-quality carbohydrate was defined as carbohydrate from fruits, vegetables, whole grains, and legumes.

The women completed follow-up questionnaires 32 years after the start of this study to determine if they had developed any of 11 chronic diseases or conditions (cancer, type 2 diabetes, heart attack, bypass surgery or angioplasty, congestive heart failure, stroke, kidney failure, COPD, Parkinson disease, multiple sclerosis, and ALS). If they had not developed any of these diseases, they were considered to be “free from chronic disease.” No impairment in memory was defined as having at most 1 memory impairment. Subjects who were classified as having no impairment in physical function were able to walk a few blocks. Good mental health was defined as a Geriatric Depression Scale score of 1 or less.

What did this study find?

At the end of the study period, 7.8% of the women met the definition for healthy aging. The women with the highest intakes of high-quality carbohydrate and the highest intakes of total carbohydrate had the highest probability of healthy aging. Higher intakes of carbohydrates from whole grains, fruits, vegetables, and legumes were all associated with a higher likelihood of healthy aging. Higher intakes of refined carbohydrates and of starchy vegetables (including potatoes, corn, and yams) were associated with a lower likelihood of healthy aging. Higher fiber intakes overall and higher intakes of fiber from fruits, from vegetables, or from cereals were all associated with a higher probability of healthy aging.

When statistical techniques were used to model what would be likely to happen if 5% of the calories that the women got from carbs was replaced with total protein, animal protein, plant protein, or unsaturated fat, there was a 7% to 37% lower likelihood of healthy aging. When 5% of calories from refined carbs, animal protein, total fat, or trans-fat were replaced with high-quality carbs, there was an 8% to 16% higher likelihood of healthy aging.

These results suggest that choosing more high-quality carbs and fewer refined carbs may be an important way to increase your chances of healthy aging. So, don’t eliminate carbs. Instead, do your part to change the average American intake of 80% of carbs in the refined form and 20% in the unrefined form. Try for 50% or more of your carbs in the unrefined form.

Reference:

Ardisson Korat AV, Duscova E, Shea MK, et al. Dietary carbohydrate intake, carbohydrate quality, and healthy aging in women. JAMA Netw Open. 2025;8(5):e2511056.

To read about additional research about carbohydrates published in Vegan/Vegetarian Journal see :

Animal Product-Based Low Carb Diets Associated with Shorter Lifespan

Low-carb Diets May Not Be Ideal After a Heart Attack

Are High Protein, Low Carb Diets a Good Idea for Weight Control?

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