Walnuts appear to activate the brain region associated with appetite control
In July of 2017, a journal article was published in Food and Nutrition Research highlighted the results of a piece of novel research that looked at walnut consumption and weight loss. Specific food choices, including the consumption of nuts such as walnuts, may be advantageous for weight loss. To examine the possible benefits of walnuts, researchers performed a secondary analysis of the HealthTrack lifestyle intervention trial. Overweight and obese participants were randomized to a control group, a group that received interdisciplinary intervention including individualized dietary advice, or interdisciplinary intervention including 30 g walnuts/day. Changes in body weight, energy intake, intake of key foods, physical activity, and mental health were monitored over three and 12 months. A total of 293 participants completed the intensive three-month study period, and 175 had data available for 12 months. The walnut group achieved the greatest weight loss at three months. The walnut group reported significant improvements in healthy food choices, and decreased intakes of discretionary foods/beverages, compared to the control group. At the 12 months follow up, weight loss remained greatest in the walnut group. Significant effects were seen after three months, with the Walnut group achieving greater weight loss and more favorable changes in food choices.
In another piece research done at Beth Israel Deaconess Medical Center and report on ScienceDaily, researchers looked at the areas of the brain that light up after consumption of walnuts. They fed subject walnuts and did scans of the brain that light up when an area is more active. After being fed walnuts, they were also shown pictures of highly desirable foods. The images indicated they the subjects were less hungry of full and the images of the desirable foods and less impact than without the walnuts.
One last study published in 2005 under the title “Does regular walnut consumption lead to weight gaic?” in the British Journal of Nutrition found evidence that conflicted with the question in the title. They concluded that the weight gain from incorporating walnuts into the diet was less than the weight loss from withdrawing walnuts from the diet. The findings showed that regular walnut consumption resulted in weight gain much lower than expected and which became non-significant after controlling for differences in energy intake.
The bottom line: Walnuts can help with weight loss and it would appear that this is due to less activity in the appetite regions of the brain. This would mean that they may suppress appetite. Including 30 grams of walnuts per day in an individualized diet may produce weight loss, decreased appetite, and positive changes in food choices.