Mixed
Improvements in diet and reductions in smoking statistically explain 68% of the observed decline in coronary heart disease incidence among women, whereas increasing obesity counteracted this decline.
Your heart disease risk is heavily influenced by your diet and smoking status. Quitting smoking and improving your diet (reducing trans fats, increasing fiber and healthy fats) can significantly lower your risk. However, maintaining a healthy weight is equally critical; gaining weight can undo the benefits of a better diet. Focus on a holistic approach: don't just fix one thing, address smoking, diet quality, and weight together.
Statistically, changes in these variables — when considered simultaneously — explained a 21 percent decline in the incidence of coronary disease, representing 68 percent of the overall decline from 1980–1982 to 1992–1994... On the other hand, the increase in body-mass index explained an 8 percent increase in the incidence of coronary disease.
Why this rating
Large prospective cohort (85,941 women), long follow-up (14 years), rigorous validation of dietary questionnaires against biomarkers, and multivariate adjustment.
Source
Trends in the Incidence of Coronary Heart Disease and Changes in Diet and Lifestyle in Women
Frank B. Hu et al. · New England Journal of Medicine · 2000
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