Nuts Do Not Lead to Weight Gain, Meta-Analysis Shows

Assortment of nuts

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Key Takeaways

  • Nuts are high in calories, leading some people to believe that eating nuts may lead to weight gain.
  • A new meta-analysis shows that nuts will not cause weight gain and may actually help with weight maintenance.
  • Aim for a 1- to a 1.5-ounce serving of nuts per day, and choose a variety because each nut seems to have a different benefit.

If you are avoiding nuts because you are worried about their high calorie count leading to weight gain, it is time to rethink this strategy. A new meta-analysis and systematic review published in Obesity Reviews looked at past studies on nut intake and weight status and found that the concern about nut consumption leading to weight gain is unwarranted.

"Nuts are a nutrient-dense food, providing a plant-based protein source, fiber, monounsaturated and polyunsaturated fats, vitamins, minerals, and phytonutrients," says Stephanie Nishi, PhD, dietitian, postdoctoral researcher, and one of the authors on the study about nuts and weight.

About the Study

The researchers looked at past studies that included almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, walnuts, and peanuts with outcomes including obesity, body weight, body mass index (BMI), and waist circumference.

Stephanie Nishi, RD, PhD

The findings showed that nut intake was not associated with weight gain and is even associated with some decreased measures of adiposity.

— Stephanie Nishi, RD, PhD

Researchers included a total of 92 reports in their analyses. Six cohort studies involved 569,910 participants from seven unique prospective cohorts. The remaining 86 studies were randomized controlled trials (RCTs) involving 5,873 participants.

In this new meta-analysis, Dr. Nishi says that the team looked at whether there should be a concern about increased adiposity with nut intake.

"The findings showed that nut intake was not associated with weight gain and is even associated with some decreased measures of adiposity," says Dr. Nishi. 

The results also showed that nuts did not raise other measures of adiposity (waist circumference or BMI) studied in adults.

"I am glad that this study came out because it reminds us to have the conversation about health versus calories," says dietitian Zach Cordell, MS, RDN.

He adds that there is often fear associated with consuming high-calorie food leading to weight gain. This study helps put some of those concerns about consuming nuts to rest.

Health Benefits of Nuts

Nuts are known to be calorically dense. That means every bite will have more calories than an equal amount of other foods, such as vegetables, fruit, or grains. Unfortunately, this fact comes with some fiction—there is a long-standing belief that high-calorie nuts should be avoided because they will cause weight gain.

What is often overlooked is that nuts are also a part of recommended dietary patterns that protect heart health, including the DASH diet, Portfolio Diet, and the Mediterranean diet.

Zach Cordell, MS, RDN

The health benefits are not just related to weight loss, but also in reducing inflammation, reducing risk for cardiovascular disease, and helping to manage diabetes.

— Zach Cordell, MS, RDN

Past studies have shown that frequent (at least 4 times a week) nut consumption can help improve blood sugar control in people with type 2 diabetes and may help lower the risk of developing heart disease.

Interestingly, past studies also show that nuts may reduce the risk of cardiovascular disease by decreasing body weight, yet the perception that nuts cause weight gain still persists.

"Nuts have been one of my consistently recommended foods for nearly all my clients," says Cordell. "The health benefits are not just related to weight loss, but also in reducing inflammation, reducing risk for cardiovascular disease, and helping to manage diabetes." 

Why Nuts May Not Cause Weight Gain

Even though nuts contain a lot of fat and calories, the researchers did not find an association between nut consumption with obesity risk. The researchers pose a few possibilities as to why. These include:

  • Unsaturated fats in nuts are more readily oxidized and have a greater thermogenic effect compared to saturated fatty acids, leading to less fat accumulation.
  • Nuts are satiating (make you feel full) due to their levels of fiber and protein.
  • The physical structure of nuts means they are not completely digested, and thus not all of the calories are used. In fact, the calorie counts of nuts may be overestimated by up to 25%.

"The physical structure of nuts may also contribute to their satiating effect because the act of chewing to break down the physical structure of nuts may modify appetite sensations," says Dr. Nishi.  

Tips for Enjoying More Nuts in Your Diet

"The amount of nuts generally recommended to consume is about 28 to 45 grams (1 to 1.5 ounces) a day for their health benefits," says Dr. Nishi. That's a small handful of nuts.

While nut intake has marginally increased in the last 10 years due to these recommendations, intake levels have remained well below the suggested guidelines, and nuts are certainly not the cause of obesity in North America.

Cordell says that flavored, raw, roasted, or unsalted nuts can all have a place in a healthy diet, but recommends limiting nuts that are loaded with added sugars. He says you may not be getting the full benefit of the nut if it feels like you are eating candy.

"When incorporating nuts into an eating pattern, try replacing a less nutrient-dense snack or food item (such as cookies or chips) if these are usually consumed," says Dr. Nishi.

If you already eat a relatively healthy dietary pattern, Dr. Nishi suggests incorporating nuts in cereal or yogurt, adding them to salads, soups, or pasta, sautéing them with vegetables, or packing a handful with fruit for a snack on the go.

As for which nuts are the best choice, most experts agree that all nuts are good choices. Each nut seems to have a different benefit, so enjoying a variety of nuts is a smart approach. For instance, almonds and pistachios have the most calcium, pecans are richest in antioxidants, walnuts boast the most omega-3 fats, and cashews are highest in iron.

What This Means For You

Nuts are a smart choice as part of a healthy eating pattern. They contain an array of vitamins and minerals, plus fiber and protein to help you feel full. They are not a cause of weight gain but may actually help with weight control efforts. Aim to eat a small handful of nuts (1-1.5 oz.) about four times a week.

7 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Cara Rosenbloom, RD
 Cara Rosenbloom RD is a dietitian, journalist, book author, and the founder of Words to Eat By, a nutrition communications company in Toronto, ON.