Every man is a Tardis; defined by a rigid structure on the outside and containing infinite possibilities within. I think the most common misperception about weight loss is that it's a physical act. You move your body, you eat the right food, and then your results happen.
Yes, the Tardis travels, but it's what's inside that gets it from place to place.
More important than your physical ability to become more athletic and active is the decision to take the first step, the second, and so on. It takes a strength of mind and sense of vigilant determination that I'm not sure everyone is ready to deal with, especially if what you're seeking is a major transformation.
Losing 100 lbs took a little under a year for me and in that year, my size wasn't the only thing that changed. It was a little bit like regenerating. I discovered I had a "fighting hand." I confronted my demons, I stood up for myself when I felt I was being mistreated, and when I made mistakes I fought to get back on track. Those were not things that were a part of my personality before hand, but they feel like a second skin now.
The fact is that life is going to hand you a lot of distractions that fall outside of your rigid little plan of action. During the last year, I had to constantly ask and remind myself why I was putting myself through it. I reminded myself of all the things I was rejecting from my life and why. I had to get in touch with why I was worth getting up at 6AM to run, why my decision to not enjoy Holiday season treats along with everyone else for one year was a necessary step, and why I should keep exposing myself to new workouts, and nutrition knowledge despite being comfy with my routine. I got in touch with what I wanted. I wanted to be able to go to the doctor and not have my weight be an issue. I wanted to cosplay with confidence. I wanted to be able to experience a more physical body. I wanted to salvage a chance at a career in the entertainment industry. I wanted to be proud of every part of myself and know beyond a shadow of a doubt that I live without regrets.
What you want can change, but it's important to keep revisiting it or you'll lose direction and focus. Hell I wanted to be an astronaut more than ANYTHING when I was younger. I still want it, but it was unrealistic given my complete lack of mathematical prowess. It felt like an earth shattering regeneration when I realized I needed to look somewhere else for a goal and drive, but it's what has made me who I am today and it got me in touch with my more natural inclinations and talents as a story teller and as a performer. I'm sure I'll face a ton of wibbly wobbly timey wimey transformations throughout my life as I learn more specifically what I want, but as long as I keep asking the question, I think I'll get where I'm going.
When it comes to your health, keep asking yourself what you want. Don't be afraid to change things up as long as you keep traveling. Don't be afraid to end up in the wrong place and learn from it. Don't be afraid when you see your personality changing along with your physical body. Don't be afraid of the destination when you arrive.
Don't blink. Not because of the angels, but because if you do, you might miss all the fantastic nuances of the journey you're on. You won't remember the number on the scale as much as you'll remember everything you learned on the way there. That's what will keep you traveling in the end.