Pecan nut diet and heart health in overweight adults
What it found
In overweight and obese adults, a pecan-rich diet improved insulin resistance, fasting insulin, and beta cell function compared with a nut-free control diet.
The pecan diet also lowered a combined score of heart and diabetes risk markers.
What they found
Studies in people
Insulin and blood sugar
After 4 weeks on the pecan diet, serum insulin, insulin resistance (HOMA-IR), and beta cell function (HOMA-β) improved significantly more than on the control diet. Fasting glucose was lower with pecans but the difference was not statistically significant.
Combined risk score
A composite score of five cardiometabolic markers (insulin, glucose, total cholesterol, triglycerides, and LDL) decreased by 0.14 standard deviations with the pecan diet and increased by 0.25 with the control diet. The difference between groups was statistically significant.
Cholesterol changes
Total and LDL cholesterol were lower after the pecan diet, but the differences compared with the control diet were of borderline significance. Red blood cell levels of monounsaturated fats and oleic acid rose significantly with pecans, while palmitic acid fell.
Antioxidants and inflammation
No significant differences between diets were seen in tocopherols, total phenolics, antioxidant capacity, oxidative stress, inflammation, or endothelial function. Levels of gamma-tocopherol increased with pecan consumption while alpha-tocopherol decreased.
Blood pressure and weight
Blood pressure was lower with the pecan diet but the difference was not statistically significant. No significant changes in body weight occurred over the study period.
What the authors conclude
“The dietary change assessed in this study, displacing a portion of the saturated fat in a typical American diet and enhancing phytochemical intake with a handful of whole pecans daily, can protect adults at risk for developing CVD and T2DM due to their age, overweight status, and body fat distribution.”
Also in their conclusions
- They conclude that displacing a portion of saturated fat in a typical American diet and enhancing phytochemical intake with a handful of whole pecans daily can protect adults at risk for developing cardiovascular disease and type 2 diabetes due to their age, overweight status, and body fat distribution.
- They state that further investigation of nut consumption on the prevention of cardiometabolic risk in at-risk populations is warranted, as are more studies examining the potential benefits and mechanisms of regular pecan consumption.
How it was done
The authors wanted to learn whether eating pecans could improve risk factors for heart disease and type 2 diabetes beyond just cholesterol, especially in people who are overweight or obese and more likely to develop these conditions.
They ran a 12-week randomised controlled feeding trial with 26 overweight or obese men and postmenopausal women, aged 45 or older, with central adiposity. For two 4-week periods, participants ate either a pecan-rich diet (15% of calories from pecans, about 42.5 g per 2000 kcal) or a control diet matched for total fat and fibre but without nuts, with a 2-week washout between periods.
What it can’t tell you
- The study was small (26 people) and lasted only 4 weeks, so it cannot show what happens over longer periods or in larger groups.
- The findings apply to overweight or obese middle-aged and older adults with central adiposity, not to everyone.
Who paid
- Conflicts
- The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.
- Authors work at
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, USA; Tufts University School of Medicine, USA
The paper
- Title
- A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- McKay DL, Eliasziw M, Chen CYO, Blumberg JB (2018). A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. Nutrients. doi:10.3390/nu10030339Free full textPubMed 29534487DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error