I stumbled upon Mark's Daily Apple about a year and a half ago. He emphasizes a paleo-diet (basically plants and animals) and 4 basic exercises (push ups, pull ups, squats, & planks) that every man should be able to do. I adopted the high protein, high saturated fat, low carbohydrate diet along with the exercise regime. I throw in some arm exercises (curls and tricep extensions) as I always wanted large arms. I also run once a week ~ 5miles. I make Sunday Runday.
I read in a magazine about 10 years ago that a 40 year old can be in better shape than a 20 year old. I now believe it! I am now 43 years old and in better shape than most 30 somethings and a lot of 20 somethings. To boot, being 43 I am the boss of some of those guys.
I am confident when I take my shirt off in public and have started Crossfit to increase strength and further improve my overall fitness.
Best part is the diet. I never go hungry! I watch what I eat, but I basically look for high quality food that is high in protein and saturated fat. Bacon is yummy and good!
Its funny - it all started with a decision to make myself better.
After you make the decision, I recommend you start here -
www.marksdailyapple.com
If I can do it, you can do it!
Best of luck!