Adherence to the 2007 WCRF/AICR cancer prevention recommendations has been associated with lower cancer risk but the underlying biological mechanisms have not been elucidated. We utilized dietary and lifestyle data from 11,342 women in the Nurses’ Health Study and 8,136 men in the Health Professionals Follow-up Study, to investigate associations between adherence scores and markers of inflammation, hormonal and insulin response. Two scores ranging from 0 to 3 were constructed to assess adherence to the energy balance-related recommendations (weight management, physical activity, energy density); and the plant, animal foods and alcohol intake recommendations; with higher scores indicating greater adherence. The following biomarkers were assessed in plasma samples donated by chronic disease-free women (1990) and men (1994): C-reactive protein (CRP), interleukin-6 (IL6), tumor necrosis factor alpha receptor 2 (TNFαR2) and adiponectin for inflammation; estrone and estradiol for hormonal response in women, C-peptide for hyperinsulinemia; and triglycerides/high density lipoprotein-cholesterol (TG/HDL) ratio for insulin resistance. In multivariable-adjusted linear regression analyses, we estimated relative concentrations of biomarkers across adherence categories. There was a significant trend of lower (higher for adiponectin) biomarker concentrations with higher adherence to the energy balance recommendations (all P-trend<0.0001). Comparing the highest (3) to the lowest recommendation category (0–1), the percent difference in relative concentrations of biomarkers was CRP, −69%; IL6, −41%; TNFαR2, −13%; adiponectin, +36; C-peptide, −43%; TG/HDL, −43%; estrone, −31%; and estradiol, −43%; in women; and CRP, −59%; IL6, −42%; TNFαR2, −10%; adiponectin, +22%; C-peptide, −44%; and TG/HDL, −40%; in men. In contrast, associations between adherence to the plant, animal foods and alcohol intake recommendations and biomarker concentrations were weaker, and mostly nonsignificant. The healthier biomarker profile associated with greater adherence to the WCRF/AICR cancer prevention recommendations is driven mainly by adherence to the energy balance-related recommendations.