Common ingredients in processed foods to avoid include added sugars, sodium, and trans fats. Added sugars are linked to various health issues, such as weight gain and increased risk of diabetes. High sodium levels can contribute to hypertension and heart disease. Trans fats, often used for longer shelf life, are detrimental to heart health and can raise bad cholesterol levels. Additionally, one should be cautious of artificial additives and preservatives, which may have adverse health effects. Reading food labels is vital for making healthier choices.