The Study
Walnut consumption in a weight reduction intervention: effects on body weight, biological measures, blood pressure and satiety
This study is like a fair race between two diets: one with walnuts and one without. Both groups lost weight, but the walnut group had better blood numbers. We can't say walnuts alone caused the improvement because everyone was also eating less and exercising — but it's a strong hint that walnuts helped.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
People who ate walnuts every day while dieting lost just as much weight as those who didn’t, but their bad cholesterol dropped more and their blood pressure stayed lower.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 576 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — lowering LDL by 9 mg/dL and keeping blood pressure down can reduce heart attack risk, even if weight loss is the same as other diets.
- 2Walnut group lost 8.9% of body weight (same as control); LDL cholesterol dropped from 121 to 112 mg/dL; systolic blood pressure stayed lower at 6 months; HDL cholesterol didn’t change; blood levels of healthy fats increased.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrition Journal
Year
2017
Authors
C. Rock, S. Flatt, H. Barkai, B. Pakiz, Dennis D. Heath
Related Content
Claims (6)
People who eat about 15 grams of walnuts each day have a lower risk of dying from any cause compared to those who do not.
Overweight and obese adults who eat 28–42 grams of walnuts daily while on a calorie-restricted diet lose the same amount of weight as those on a standard low-energy-density diet, but experience a 9 mg/dL greater reduction in LDL cholesterol and lower systolic blood pressure after 6 months.
Eating walnuts while losing weight through calorie restriction does not raise HDL cholesterol levels in overweight or obese adults, and men who ate walnuts started with lower HDL cholesterol than those who did not.
In overweight and obese adults, losing at least 5% of body weight is linked to a drop in total cholesterol by 13 mg/dL, while losing less than 5% is linked to a rise in total cholesterol by 18 mg/dL, and the amount of weight lost matters more for cholesterol change than eating walnuts.
In overweight and obese adults following a calorie-restricted diet, eating 28–42 grams of walnuts daily does not change how full, hungry, or satisfied they feel compared to eating other foods with similar calorie density.
In overweight and obese adults following a calorie-restricted diet, eating 28–42 grams of walnuts daily raises levels of alpha-linolenic acid and linoleic acid in the blood, and these changes are linked to lower LDL cholesterol and reduced blood pressure.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.