I love to eat so I don't see myself curtailing my diet. 
But crap I used to get out there and do 100 yard sprints with little stretching or warm up and got them out of the way quickly. Now it takes longer to get ready and then it's a nag to do the 100 yard sprints. Yesterday after doing 6 I had to shorten the next couple to 50 yard sprints. Also, my speed seems to be disappearing. 
Your base/resting calorie burning (I think it's called metabolic rate or something) gets worse as you get older.
