I hear you about not being 20 anymore. Weight is the big thing but it really does matter what you eat. Lots of meat slows you down - literaly! Too much fat clogs the small capilaries in your brain and that's also why you get tired so fast. I am 52 years old and can still run up a 20 foot ladder and not be winded. Eat mediteranian with lots of whole grains, fruits, vegetables, and you will outwork your apprentices. Meat makes arthritis worse too and that can be scary.