Pistachios Help Supplement Weight Loss Plans, Study Finds

A new study shows that adding pistachios to a behavioral weight loss program can result in positive outcomes like healthier body weight and lower blood pressure.

The new data challenges old ways of thinking about fat in our diets. Previously, experts recommended avoiding all fats, assuming that excessive consumption would cause weight gain and have negative cardiac outcomes.

“As a dietitian who's lived through decades of fatphobia with clients, it's exciting to see research like this recent pistachio study emerge, yet again showing the power of eating healthy fats to achieve weight loss and other health-related goals,” Elizabeth Shaw, MS, RDN, CPT, a nutrition expert at Shaw Simple Swaps, tells Verywell. 

Pistachios are a source of dietary fat, but it's not the same type of fat that is found in heavily processed foods. Instead, pistachios contain heart-healthy monounsaturated fats, which have been linked to many positive health outcomes. 

The results of the new study, which were published in Nutrients in July 2020, show that it's not necessary to avoid heart-healthy fats (found in foods like nuts, olive oil, and avocados) to meet weight and other health goals. In fact, in some cases, avoiding fat can be counterproductive.

To find out whether pistachio consumption could be used as a beneficial part of a weight loss program, researchers at the University of California, San Diego studied 100 adults: some who were healthy, some who were overweight, and some who were obese.

The participants were all provided the same physical activity, dietary, and behavioral advice to support weight loss. Over a 4-month timeframe, half of the subjects in the study added 1.5 ounces of pistachios (a little over a handful), to their daily diet. The other half of the study participants did not add pistachios to their diet.

At the end of the four-month period, both groups had lost about 5% of their body weight and decreased their body mass index (BMI). However, the group who ate pistachios daily also had improved systolic and diastolic blood pressure, increased fiber intake, and lower consumption of sweets compared with those who did not consume pistachios. 

The results are promising, but the study did have limitations. “While the findings of this study are based on the 84 participants who made it to the end and I'd love to see a larger sample size in future research, this does help support the decades of research promoting consumption of nuts as part of a heart-healthy diet," Shaw says.

Pistachios and Weight Loss

From almonds to walnuts, including nuts in a balanced diet has been linked to many positive health outcomes, including weight loss. However, pistachios appear to be the darling in the weight-loss data world.

“While all nuts have health benefits, pistachios are the ones I recommend most often to clients, especially for those looking to lose weight,” Martha McKittrick, MS, RDN, a New York City-based registered dietitian, tells Verywell. The reason is that you get a bigger bang for your buck in terms of nutrition.

“Per 1 ounce of nuts, you get 49 pistachios versus only 24 almonds or 18 cashews," McKittrick says. “Pistachios are also packed with fiber, protein, healthy fats, vitamins, minerals, antioxidants, and cholesterol-lowering phytosterols."

Adding foods like nuts to your diet appears to help with weight loss because they are filling, making you less inclined to reach for foods that aren't as nutritious.

Pistachio consumption, in particular, is linked to increased satiety in healthy people assigned female at birth. If you feel full, you're more likely to consume fewer calories, which can support weight loss.

Eating pistachios in the shell also leads to more mindful eating, since you have to take time to crack the shells. In one study, people who ate in-shell pistachios instead of pre-shelled pistachios consumed 41% fewer calories from the nuts. The researchers thought this could be because of the additional time that was needed to shell the nuts, or the extra volume perceived when consuming in-shell nuts.

More Ways to Support Weight Loss and Heart Health

While eating pistachios appears to support weight loss goals, adding them to your diet isn’t the only way to support your health. 

Shaw points out that managing your portion sizes is also important. While the subjects in the study were provided with 1.5-ounce portions of pistachios, many Americans Shaw has counseled struggle “with just sticking to the portion when they themselves are measuring—or eating straight from the bag."

To combat the portion challenge, Shaw advises clients to purchase un-shelled pistachios. Another option is to serve yourself a pre-portioned helping rather than noshing on nuts right out of the container. 

Along with including a portion of pistachios into a diet, Shaw says that those who are focused on weight management or heart health should consider other positive lifestyle changes. “For instance, the participants in this study engaged in activity and a reduced-calorie diet in comparison to their normal intakes," she says.

A few simple ways to support weight loss goals include:

• Adding protein to your meals and snacks
• Drinking water
• Exercising
• Getting enough restful sleep

If you're a fan of pistachios, adding them to your morning oatmeal, having a handful as a mid-day snack, or sprinkling the nuts on salmon or a salad for dinner can help you reach and maintain your health goals.