Nuts / Omega 6 fats
The significant benefit of adding nuts to your diet is probably due to the high level of Omega-6 fatty acids in nuts. There have been many studies showing the benefit of a diet high in Omega-6 fats, as opposed to meats, especially beef, which are high in Omega-3s and low in Omega-6s. In addition, some fat in your diet adds to a feeling of fullness, and so often fewer calories are consumed in a meal, and calorie reduction has also been shown to increase lifespan.