A philosophy of life and personal hygiene that views health as not merely the absence of illness but the full realization of one's physical and mental potential, as achieved through positive attitudes, fitness training, a diet low in fat and high in fiber, and the avoidance of unhealthful practices (smoking, drug and alcohol abuse, overeating).Wellness programs are widely offered by employers, health insurance programs, and social service agencies. Formal programs typically include preventive measures (e.g., immunizations against pneumococcal pneumonia and influenza in the elderly) and surveillance for common diseases (e.g., hypertension, diabetes mellitus, and breast and colon cancer). Such programs tend to attract people already attuned to healthful attitudes and practices. Little clinical evidence exists to support their usefulness or justify their expense.