Tree nuts, a useful tool in weight management? Study identifies satiating benefits

04-May-2021 - Last updated on 04-May-2021 at 17:04 GMT

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Known as a source of healthy fats and protein, mixed tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) may also be an effective weight management tool, finds a new study published by UCLA researchers.

In a randomized, controlled study published online in the journal, Nutrients, researchers found that including 1.5 ounces of mixed tree nuts as part of a weight management program was associated with improved satiety among study participants.

"This latest study adds to a growing body of evidence showing that nut consumption may be a useful tool in weight management," said Maureen Ternus, M.S., R.D.N, executive director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF), which supported and funded the study.

Weight management in focus

Weight management is an underlying consumer health trend with 43% of Americans claiming to follow a specific diet or eating pattern in 2020 (up from 38% in 2019) citing weight loss as a top motivator, according to the International Food Information Council’s 2020 annual Food & Health Survey.

The topic of weight loss and weight management has become even more prominent in the past year as consumers found themselves confined to their homes and on-the-go behavior dropped dramatically – one study estimates an average weight gain of 1.5 pounds per month.

"We know most people get about 25% of their calories each day from snacks and a large proportion come from desserts, sugar-sweetened beverages, sweets, and salty snacks," noted lead researcher, Zhaoping Li, MD, PhD, Professor of Medicine and Chief of the Division of Clinical Nutrition at University California, Los Angeles.

"Replacing just one of those snacks with 1.5 ounces of tree nuts may result in a positive impact on weight and overall health," claimed Dr. Li, adding that tree nuts' macronutrient profile makes them satiating.

Study methods and results: Mixed nuts vs. pretzel snacks

Researchers at UCLA compared 95 overweight/obese men and women (BMI 27.0-35.0) ages 30-68 years who consumed either 1.5 ounces of mixed tree nuts or a pretzel snack. Both snacks provided the same number of calories, as part of a hypocaloric weight loss diet (500 calories less than resting metabolic rate) over 12 weeks, followed by an isocaloric weight maintenance program for an additional 12 weeks.

At the end of 12 weeks, the mixed tree nut group lost -1.6kg on average whereas the group consuming pretzels lost -1.9 kg. At 24 weeks, the mixed nut group had lost -1.5 kg and the pretzel group lost -1.4 kg, from baseline starting weights.

While both groups experienced weight loss over the 24 weeks, the group consuming mixed nuts "showed a significant increase in satiety at 24 weeks," wrote researchers who measured satiety by asking participants to score their satiety on a hunger scale from 0 to 7 (0 = starving and 7 = stuffed to the point of feeling sick).

"At baseline, there was no difference in satiety scores between the MTN (mixed tree nut) and PS (pretzel snack) groups. At 24 weeks compared to baseline, satiety was increased significantly in the MTN group," wrote researchers.

This may account for why during the weight maintenance portion of the study, participants who snacked on nuts maintained their weight loss, while those who consumed the pretzels "experienced a trend to weight increase during the weight maintenance phase," according to the study.

Additionally, more participants consuming tree nuts completed the study vs. those who ate pretzels, indicating a stronger trend towards sustainable weight maintenance compared to the pretzel group as the dropout rate among study participants was significantly lower in the mixed tree nut group (16.4%) compared to the pretzel (35.9%) group.

Researchers noted a few limitations for the study including a lower number of participants than planned due to the COVID-19 pandemic. The other limitation, they said, is the significantly higher dropout rate in the pretzel control group compared to the mixed tree nut snack.

“The choice of another control snack might reduce drop out and might demonstrate a difference in weight loss between the tree nut and the control group. In addition, we matched the calorie of the two snacks but not the macronutrient composition. Because the study was performed in free-living participants who provided their own food, we do not have data on their background diet.”