Diet's don't work. Lifestyle changes do.
No matter what new weight loss schemes arise, there's no way around watching what you eat (nutrition) and working out (exercise). Hard work and discipline are key. There are no shortcuts. Just long term investments.
So what applications do these two areas have towards your career?
Nutrition. What you put in is what you get out. Body, mind, soul, etc. Head knowledge is good, but experience is better. You learn skills through doing them. There's no point learning something if it just stays in your head. Get out there and practice what you know. You can learn through formal teaching, reading, researching or listening to others. The key is implementation. Use those "nutrients" you've absorbed towards benefiting others.
Exercise. When it comes to working out, it's not about perfect attendance, but each day starting a new streak. Begin where you are right now. Think about your personal network. Is it where you want it to be? Can it be better? (The answer to the last question is always yes, by the way) You don't have to grow your network daily, but you should have a weekly goal. It can be quantity (size) or quality (strength of connection). Either way, get to it. Your personal network is your greatest career asset (and always will be).
Try this "reframing" exercise. As a leader you have two daily challenges:
What new skills are you developing? (task-related)
How are you growing your network? (relationships)