19 August, 2017
A common theme among dieters-especially those that fail-is that calorie restriction leads to bouts of hunger, which often causes binge-eating episodes or complete abandonment of a diet regimen. Thus, the walnuts are also appetite suppressor. While the results for many of these approaches are subjective, based on participants' feeling of satiety, few have clinical evidence to support their claims.
To figure this out, researchers at Beth Israel Deaconess Medical Center used functional magnetic resonance imaging (fMRI) to watch how eating walnuts changed brain activity. As a outcome, walnuts appear to be useful in preventing obesity and possibly type 2 diabetes. (Another recent study had already proven that point.) But the participants also weren't experiencing cravings for junk food-and with the fMRI tests, the researchers could see, for the first time, why. The volunteers were asked to live in the controlled environment of BIDMC's Clinical Research Center for two five-day sessions. During the study, the researchers kept close tabs on the volunteers to know their exact nutritional intake. During one session, everyone drank daily smoothies made with 48 grams of walnuts, the recommended serving by the American Diabetes Association. During the other session, participants drank smoothies, too-but these beverages, while nutritionally comparable, were walnut-free. This means that some volunteers were taking the walnut smoothie while others were on the walnut-free diet.
As per previous studies, when participants consumed the walnut smoothies, they reported feeling less hungry during the week. While in the machine, they were shown a variety of images, including shots of neutral objects, photos of desirable foods such as hamburgers and desserts, along with pictures of less desirable but healthier foods. The fMRI imaging showed that the activity of right insular part of the brain increases when it detects food like walnuts and hence helps in making the body feel full.
"This is a powerful measure", noted senior study investigator Christos Mantzoros, M.D., D.Sc., Ph.D., director of the Human Nutrition Unit at Beth Israel Deaconess Medical Center and professor of medicine at Harvard Medical School.
The author of the studies revealed that we people never want to know how the eating habits impact the brain activity.
This shows that they were paying closer attention to food choices, allowing them to select the healthier, less desirable options over the tempting junky ones, the researchers explained in a statement.
Farr and Mantzoros next plan to test different amounts, or dosages, of walnuts to see whether more nuts will lead to more brain activation or if the effect plateaus after a certain amount.
The researchers have conducted experiments on ten persons.