Background Obesity is a precursor to heart failure with preserved ejection fraction. Biomarkers that identify preclinical metabolic heart disease ( MHD ) in young obese patients would help identify high‐risk individuals for heart failure prevention strategies. We assessed the predictive value of GAL3 (galectin–3), FSTL3 (follistatin‐like 3 peptide), and NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) to identify stage B MHD in young obese participants free of clinically evident cardiovascular disease. Methods and Results Asymptomatic obese patients (n=250) and non‐obese controls (n=21) underwent echocardiographic cardiac phenotyping. Obese patients were classified as MHD positive ( MHD ‐ POS ; n=94) if they had abnormal diastolic function or left ventricular hypertrophy and had estimated pulmonary artery systolic pressure ≥35 mm Hg. Obese patients without such abnormalities were classified as MHD negative (MHD‐NEG; n=52). Serum biomarkers timed with echocardiography. MHD ‐ POS and MHD‐NEG individuals were similarly obese, but MHD ‐ POS patients were older, with more diabetes mellitus and metabolic syndrome. Right ventricular coupling was worse in MHD ‐ POS patients ( P <0.001). GAL 3 levels were higher in MHD ‐ POS versus MHD ‐NEG patients (7.7±2.3 versus 6.3±1.9 ng/mL, respectively; P <0.001). Both GAL 3 and FSTL 3 levels correlated with diastolic dysfunction and increased pulmonary artery systolic pressure but not with left ventricular mass. In multivariate models including all 3 biomarkers, only GAL 3 remained associated with MHD (odds ratio: 1.30; 95% CI , 1.01–1.68; P =0.04). Conclusions In young obese individuals without known cardiovascular disease, GAL 3 is associated with the presence of preclinical MHD . GAL 3 may be useful in screening for preclinical MHD and identifying individuals with increased risk of progression to obesity‐related heart failure with preserved ejection fraction.