Nuts and Weight, BMI, and Waist Circumference
Not long ago we wrote about a study of walnuts that suggested that eating nuts would help you reduce your risk of developing type 2 diabetes. This was just the latest of many studies that focus on the benefits of eating various kinds of nuts. These benefits include improving your cholesterol scores with pistachios or any nut, reducing your risk of metabolic syndrome, and increasing your magnesium intake, which helps you avoid type 2 diabetes.
We've also reported that eating nuts in place of other types of snacks can help you lose weight, although it's worth noting that one research article does not necessarily mean certainty. What helps is what is known as a meta-analysis, in which researchers pool the results of several well-designed studies. These meta-analyses are held to yield far stronger results than those of the smaller studies on their own.
Researchers in Spain performed a meta-analysis of 33 studies that together included over 1,800 persons and lasted as long as 3 years (Am J Clin Nutr 2013;97(6):1346-55). Most of the studies were comparing diets with the same amount of calories and only differed in the amount of nuts the participants ate. Some diets were designed to reduce the number of calories the participants ate (in order to effect weight loss), while others were designed to maintain the participants' weight.
When they focused on those studies that looked at body weight ( as opposed to Body Mass Index), the Spanish researchers found that when the diet did not involve a reduction in the number of calories, people did not lose weight by eating nuts. On the other hand, those who did eat nuts while reducing their caloric intake did seem to lose more weight. Not a clinically significant amount of weight, but certainly a measurable amount.
In other studies focusing on Body Mass Index (BMI) they found that eating nuts did help reduce BMI by, again, a clinically insignificant amount. Once again, the effect was greater when the participants were following a reduced-calorie diet rather than one designed to help them maintain their weight. Looking at studies that focused on waist circumference yielded similar results: larger effects for reduced-calorie diets.
What this means for you
Despite their higher levels of fats, snacking on nuts in place of the same number of calories of other foods may actually help you lose weight, whether you're actively reducing the number of calories you eat or not. Choose nuts instead of chips or pretzels the next time you want a crunchy snack. They're satisfying and great for you in so many ways.
First posted: May 29, 2013