Trying to reverse my 40lbs gain/how to stay consistent?

Hello everyone

I have register here few years ago when I started to gain my first extra pounds...now situation get pretty serious since I have gained really a lot in a short period of time..

When I've started to work at home, my weight just exploded. I have lost almost all of my great habits that I used to have: daily walk to work, having fixed meals with no or little snack in between, lot's of veggies and cooked food, very little junk food.

In a small period of time I've started to experience problems with my knees, and that was trigger to start some changes.

I have read a lot about nutrition & fitness, now I have to put all that theory into practice. One thing that I am really bad at and really need help with is consistency...I am pretty stubborn and dedicated for some time, but then something happens and I just let myself go with the flow...

Do you have any advice how to make sure that the "future me" will stay motivated and on track as I am now?