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  • A new study looks at how eating more fiber and less starchy foods affects your weight over time.
  • Making these diet changes is linked to a decrease in weight gain over time.
  • The study looked at over 136,000 people with an average age of 51.

New research published in the British Medical Journalhas found that increasing the amount of whole foods, fiber, fruits, and non-starchy vegetables you consume is linked to a decrease in weight gain over time.

The study included 136,432 people, all of whom were part of the healthcare field and were defined as being “mid-life” with an average age of 51.6 years old.

Researchers found the quality of the carbohydrates you consume has a significant impact on the weight that you gain over long periods.

Amanda Sauceda (MS, RD), who works both in her own private practice and as a lecturer at Cal State University–Long Beach, says that while the research didn’t necessarily unveil anything earth-shattering, it did shine a light on some of the lesser discussed areas of one’s diet, including the role of fiber.

“It is the most unsexy thing in nutrition. It’s not exciting to talk about fiber, but I think it’s so under-loved or underappreciated because it is so powerful.”

On average, those involved in the study saw a 1.5 kg ( about 3.3 pounds) weight gain every four years. If we dig a little deeper, the researchers found that those who added just 100 grams a day of starches saw a 1.5 kg higher increase in weight gain over four years.

In comparison, those who added 10 grams a day of fiber saw 0.8 kg (1.7 pound) less weight gain. Examples of starchy vegetables include peas, corn, and potatoes.

That distinction, looking at differences in weight gain versus weight loss, is something that Kimberly Gomer (MS, RD/LDN, a Florida-based dietician in private practice, says is vital to keep in mind when it comes to looking at the diets of Americans.

“Better is better, you know, so it’s better to gain five pounds in five years than to gain twenty pounds in five years. So, I think that’s a very realistic way of looking at Americans because the trajectory is not that Americans stay the same. They gain weight.”

The study focused on those in “mid-life,” a demographic that Kesley Costa (MS, RDN), registered dietitian and nutrition consultant for the National Coalition on Healthcare, says is consistently faced with specific barriers to adequate nutrition and sustaining their weight at their desired level.

“These challenges range from dealing with the metabolic changes associated with aging, such as lower metabolism and altered body composition, to managing the onset of age-related conditions like hypertension and diabetes, which necessitate dietary modifications. Individuals in mid-life may also face time constraints due to career and family responsibilities, making it more challenging to prioritize healthy eating habits.”

The participants did not have medical conditions such as diabetes, cancer, cardiovascular disease, respiratory disease, neurodegenerative disorders, gastric conditions, chronic kidney disease, and systemic lupus. So it is unclear if the findings would apply to those groups as well.

Gomer, who has taught nurses throughout her career, says that the fact that the participants worked in healthcare is something to pay attention to for those in the field, even if the findings of the study do indicate that the results can be generalized to the general public.

“They have horrible hours, and horrible shifts; they don’t have time to eat,” Gomer says. “And when they do have time to eat there’s a lot of bad food being brought in.”

Another limitation of any study like this, which the researchers identified, is that self-reported data when it comes to nutrition is prone to under-reporting. According to Gomer, short of following people around at home, it is next to impossible to get entirely accurate information on the individual level.

Costa says that even if this research did not include people with certain conditions, her advice is that evaluating your carbohydrate intake can still be valuable.

“For those with diabetes or other conditions that were not included in the study data, there is still value in incorporating these dietary recommendations,” Costa said. “A diet rich in high-quality carbohydrates can help improve blood sugar control, reduce the risk of cardiovascular disease, and promote overall health.”

Experts said there are easy ways to increase your fiber intake and reduce eating starchy foods.

Sauceda says that people tend to lean on foods they grew up eating, but that the same need for convenience that draws us to high glycemic index foods (like french fries) can be used to increase fiber.

“I think easy places to start when it comes to fiber [rich] foods is like nuts and seeds. Because when you think about people who are busy, nuts and seeds take no prep, right? You can keep it in your bag, or in the office, or just easily on the counter.”

Another place she starts with her students is to have them look at the drinks they are bringing into class, liquids that are often high in added sugars. Costa, meanwhile, says that there are staples you can lean on if you’re looking to increase fiber and reduce high levels of starch and added sugar.

“Identifying ultra-processed foods that are most often consumed and systematically swapping them for whole foods is a practical approach to increasing fiber and natural sugar intake. Having healthier options readily available, such as fresh or frozen fruits and vegetables, can also be helpful in making this change.”

A new study finds people who eat more high fiber foods instead of starchy meals at midlife are likely to avoid weight gain.