Between the gluten sensitivity, low-carb diets, and paleo, grains in general have fallen out of favor over the last decade or so. The original U.S. Department of Agriculture guidance published in 1992 made them foundation of the food pyramid, with 6-11 recommended servings per day. The more recent USDA guidance for MyPlate reduces the servings of grains, and advises that half of them should be whole grains.
All-cause mortality studies make a much sharper division between whole grains and refined grains. Refined grains, like white bread, white rice, or refined pasta, are practically the baseline of developed world diet. Eating more or less refined grains generally doesn’t affect longevity, positively or negatively1.
The longevity benefits of whole grains, in comparison, look unlimited. Each serving (about 1 ounce or 30 grams dry) of whole grain reduced all-cause mortality by about 8%, and the benefits of whole grains at least up to 8 servings, with little sign of decreasing benefit2.
When going through the details of the various types of food that have whole grains, like dark breads, whole-grain breakfast cereals, and other grains (bulgar, kasha, and couscous, etc.) they all show a dose-related benefit, and there doesn’t seem to be any particular category which was better or worse than the others.
Eat over 100 grams (dry weight) of whole grains, and give your diet a solid foundation for longevity!