a quote got me to start again...weight loss at 70

It sounds like you are in the right place.. both by being in MFP, as well as in the right 'head space'.

About 7 years ago (age 55) a 'quote' from my Dr got me started too ... in discussing why my blood pressure was now consistently hovering around 130/80 instead of the 120/80 it had been maintained at for many years with meds (many years before [untreated] it had been 190/90).
He attempted to reassure me it was 'still ok, just on the higher side of normal' - when I said I was concerned about it just the same, his reply was...

"Well, you are getting older, and with aging you have to expect these kinds of changes, it's just your new normal"

That got to me more than either of us expected apparently. Accept something I felt I could do something about? No darned way!

That in combination to losing my mum due to weight related issues, and watching my husband's health deteriorating (again, due to choices he has continued to make, resulting in many health issues but including type 2 diabetes and heart disease [5 stents in place now]), was the magic combination that flipped a switch in my head.

In other words... I was the only one who had a vested interest in getting me 'healthy'... so, I'd better get busy!

Within the next 10 months I lost 75 lbs, eating well, and logging every single thing.
Exercise/activity started to feel like something I 'wanted' to do (instead of just thinking it was needed), and low and behold, I then found I HAD to start eating back those calories from activity because if I did not, my weight loss actually slowed.
WooHoo!
Keep on losing, more food, feel better than I had in my entire life (have been obese since birth..literally) - what's not to love!

At end of those 10 months, I maintained about 6 months. At the right weight for my height for the first time ever felt so alive and younger than I'd felt in many many years!
And yes, blood pressure went so low Dr had to back me off it quite a bit.

And then, I felt so great, I went back to work.
Slowly, bit by bit over time, I gained too much of that back, sedentary job, mentally exhausted by end of day with no energy, lost my walking companion (my husky), and assorted other life events that seemed to take over = I forgot how good it felt to look after 'me', so I stopped doing so.

In times and diets past, I've never been able to return to a single plan that I'd done before, no matter how well it worked at the time.

But, MFP is simply tracking, focusing on recording the choices I make, all of them good and bad, and it's simply what I need. It keeps me accountable to the only person that matters, 'me'.

So, here I am again, 5 weeks in... I will be 62 this year, and 10 lbs lighter than I was 5 weeks ago
I've returned, because this really is everything I need. 'My' fitness pal indeed!

We are ALL responsible for the choices we make, those of us who have found a way to make this approach work for us, likely feel empowered by seeing just how much difference those choices can make, and moving into the next day with that in mind.

Aging?
Yes I am, and darn proud of it.. but as long as folks are flabbergasted each time I tell them how old I really am, because all they see is an active healthy woman with some laugh lines around her smile and life experience in her eyes, (and folks think I am younger than my 53 year old husband LOL), and my Dr continues to be awfully proud of me... that's all good to me.

note: My profile pic shows when I was still dying my hair 7 years ago, and was at my goal weight.
For now I am purposely leaving it there to remind myself how well I did before. I will update it as I get further along.
(Since that time I've let my natural 'all white/silver' show through (my natural colours since I was in my 40s LOL.)