Not everything that lowers HDL is bad for you. If you change from a high-fat, high-cholesterol diet to a healthy low-fat, low-cholesterol diet, your HDL levels may stay the same or even decrease because there is less need for it. When you have less garbage, you need fewer garbage trucks to remove it, so your body may make less HDL.
When we realize that something as primal as the food that we choose to eat each day makes such an important difference in addressing both global warming and personal health, it empowers us and imbues these choices with meaning. If it's meaningful, then it's sustainable - and a meaningful life is a longer life.