In the quest for longevity, nutrition plays a pivotal role. While there's a plethora of advice on what to eat to extend your lifespan, equally important is knowing which foods to avoid, especially as you age. An expert has pinpointed five specific "forbidden" foods that those over 30 should steer clear of to promote a longer, healthier life. Unfortunately, the provided sources do not directly list these five "forbidden" foods. However, based on the comprehensive insights from longevity and nutrition experts across the sources, we can infer some common dietary culprits that are generally advised against for those seeking to optimize their healthspan and longevity:

1. Processed Foods: High in salt, sugar, saturated fats, and chemical preservatives, processed foods have been linked to an increased risk of noncommunicable diseases, which are a leading cause of mortality worldwide. A diet rich in processed foods was found to result in an increased risk of premature death.

2. Excessive Red and Processed Meats: Diets high in red and processed meats have been associated with higher risks of certain cancers and cardiovascular diseases. The emphasis is on the quality and quantity of protein intake, with a recommendation for a balanced intake from healthier sources like fish, beans, nuts, and seeds.

3. High-Sugar Foods and Beverages: Excessive sugar intake can lead to obesity, type 2 diabetes, and cardiovascular diseases. It's recommended to limit foods and drinks high in added sugars to support overall health and longevity.

4. Trans Fats: Found in some fried foods, baked goods, and processed snack foods, trans fats are linked to an increased risk of heart disease and stroke. They are considered harmful even in small amounts and are advised against for a heart-healthy diet.

5. Excessive Alcohol: While moderate alcohol consumption might have some health benefits, excessive drinking is harmful and can lead to liver disease, cancers, and increased risk of accidents. Limiting alcohol intake is advised for those aiming for a longer, healthier life.

It's important to note that while avoiding these foods can contribute to a healthier lifestyle, longevity is also influenced by a combination of factors including genetics, exercise, sleep, and overall dietary patterns. Emphasizing whole, minimally processed foods, and a diverse, nutrient-rich diet alongside healthy lifestyle habits is key to promoting longevity.