"I will start Monday."
"I'm doing this tomorrow."
"I'm going to do this soon."
What these have in common is the idea of later. Everything is put off until later. Until tomorrow. Until after the weekend. Really, what's the deal with putting all your determination and drive into "tomorrow." You'll just keep saying, tomorrow..tomorrow..tomorrow.
Aren't you fully capable of starting today? What's with the magical premise that a new day is when you can become a new you? Start now. Start today. Get your ass in the gym now. Get your diet in order for the meal your about to eat. Most likely if you wait until tomorrow, you will pig out on a box of cookies tonight. Or if you are going to start Monday, you will go balls-to-the-wall this weekend at bars and going out to eat. All while saying this is the last time before I start changing my life and body.
Stop making excuses for yourself. Stop procrastinating. You don't need a new day to begin changing.