First time 5k runner

[50_is_the_new_30]

Hi everyone,

I am a running newbie.  Roughly 10 years ago, I got down to a healthier weight (5' 10", 180 lbs) .  Then surprise baby #3 came along.  Nothing like having a baby at 45.  There is a reason couples have kids in the 20's and 30's.   I got a son in the bargain though :-).  He is a lot of fun.  I did the math and will be hitting Social Security age by the time he is out of college.  

Long and short is that in June 2019 I got back on the exercise band wagon so I will be around to see him grow up (nothing like a death in the family to motivate oneself).  I have been weight training 4 to 5 days a week before going to work (upper and lower body on alternating days).  I need to drop about 45 pounds.  It's tougher this time.  My actual weight hasn't moved much.  But with that said, muscle tone has improved and I need to work on my diet (90% eating habits - 10% workout rule).

There was a poster at the gym advertising a 5k to benefit the local schools.  I have always wanted to be able to run for at least a respectable distance, so why not do a 5k.  I've paid the fee so I have scratch in the game.  Friends and family have been advised to keep me motivated.

I started the C25K program on Monday because it was obvious from past attempts that I need help.  I have some questions where I need advice.

I have been fitted by the staff at a running store and purchased shoes that assist with my pronation issues.   My ortho doctor has advised me 10 years ago that I likely have torn miniscus in both knees.  I need to have these repaired but just haven't taken the time to do it.

1. With my knee problems and overweight status, do I need a shock absorbing insert in my shoes?
2. My left knee can be very touchy if I bend down on this knee.  I make every attempt to avoid hyperextending this knee.  Should I consider one of the black neoprene knee supports that I see some runners wearing?
3. I've had a trainer tell me that I have tight hamstrings.  In the past when I've attempted running, I am getting pain in one or both ankles and my calves after several minutes of running that cause me to stop running.  Any suggestions on how to eliminate this?
4. I had some sciatica problems just over a year ago.  It took 6 to 9 months to get back to where I could walk without pain.  I have noticed some pain in the piriformis muscle that dissipates with rest and ibuprofen.  This has occurred when I've been doing squats and pushed a bit too hard with the leg work.  Are there any precautions I need to take to keep from aggravating this.  Not running is not an option.
5. Being a good Southern boy, meals have been very heavy on the four horsemen of heart disease:  sugar, salt, butter, and white flour.  Any food suggestions that don't involve eating food with the consistency and taste of cardboard would be appreciated.  I am taking a graduated approach to sodas.  Down to one sugared soda per day, fill in with diet and water.  Working toward water only.

Thanks in advance for any advice you can give.

50_is_the_new_30