A walnut-containing diet that is reduced in total calories can promote weight loss comparable to a standard reduced-calorie diet according to a new study published in Nutrition Journal. The walnut-enriched diet also showed potential benefit for two cardiovascular disease risk factors.
AICR research shows that obesity is linked to 11 types of cancer so getting to and staying a healthy weight is a key lifestyle action for lower cancer risk. This study suggests that multiple different eating patterns can support weight loss efforts.
In this six month study, 100 men and women with overweight and obesity, aged 21 and older, were assigned a reduced energy diet of vegetables, fruit and whole grains as well as lean protein sources and reduced-fat dairy foods.
One-half of the participants followed a reduced energy density diet - typically high in vegetables and fruit and low in fat - and the other half of the participants were assigned to a reduced calorie diet containing walnuts. The walnut group consumed an average of 1 – 1.5 ounces of walnuts per day which provided about 15 percent of their daily calories.
Walnuts are energy dense foods, yet observational studies have found a correlation between regular intake of nuts and better weight management, less weight gain in adulthood, and lower amounts of body fat.
After 6 months, both groups showed similar weight loss, but the walnut group showed greater decreases in systolic blood pressure and both total cholesterol (203 to 194 mg/dL) and low-density lipoprotein cholesterol (121 to 112 mg/dL), measures linked to cardiovascular health. Despite the calorie-density of walnuts, weight-loss and self-reported satiety were similar between the groups.
“In spite of the fact that nuts are calorically dense and high in fat, our findings show that eating walnuts as part of a diet to promote weight loss can be recommended,” says the author of the study, Dr. Cheryl Rock. Cheryl Rock is a Professor of Family Medicine and Public Health at University of California, San Diego. She added, “Our study shows that the type of fat in walnuts is a healthy type of fat, so there may be an additional bonus in this dietary pattern that explains the favorable effect on risk factors for heart disease.”
Participants in both groups received individual counseling, group sessions and a diet prescription and sample meal plan with the goal of a 500 to 1000 calorie deficit compared to their energy expenditure. They were all asked to increase their physical activity and gradually build up to a minimum of 10,000 steps per day within the first month and then maintain or increase that level of lifestyle activity.
Dr. Nigel Brockton, Director of Research at AICR says, “As expected, reducing energy intake and increasing activity led to reductions in measures of adiposity, in both groups. However, walnut consumption was associated with additional improvements in factors associated with cardiovascular health. Achieving and maintaining a healthy weight is a core cancer prevention recommendation from AICR. Substituting a proportion of daily calories with walnuts may help people achieve those goals, especially as part of an active lifestyle.”
Note: This study was funded by the American Institute for Cancer Research (AICR) and the California Walnut Commission through the AICR Matching Grant Program. The funding agencies had no role in the design of study, data collection and analysis, or presentation of the results.
Sources: Cheryl L. Rock, Shirley W. Flatt, Hava-Shoshana Barkai, Bilge Pakiz, and Dennis D. Heath
Walnut consumption in a weight reduction intervention: effects on body weight, biological measures, blood pressure and satiety
Nutr J. 2017; 16: 76.
Published online 2017 Dec 4. doi: 10.1186/s12937-017-0304-z
Published on January 2, 2018