Jayzoe, I know EXACTLY what you're talking about! And according to Nancy, it's a common fear.
It's a mindset. The way you go into transition and maintenance is completely different from how we view "vacation allowances." And eventually, even those morph into better choices.
Lauren has stated it several times -- this is a life-long program, not a diet phase. The MF meal replacements are simply tools to make the choices easier right now. A lot of successful maintainers continue to use them for that very reason. But it's so much more than that.
Dr. Andersen has developed this program based on his BeSlim philosophy which was the result of researching the common key elements of folks who've lost a substantial amount of weight (at least 50 lbs) and kept it off for at least 5 years (I originally said 2, but that's incorrect). There's an assessment to evaluate if you've got all the pieces in place. (Send Mike a PM and he can tell you more.) In those times when you're unsure during transition and maintenance, go back and take the assessment. It makes it clear what things you've got in place, what areas you need to pay more attention to, and helps you decide if what you're doing is going to keep you on track.
By the way, you and I are in the same boat, vacation-wise. I just came back from a badly managed Memorial Day weekend. It still happens.
The difference, though, is we, you and I, get right back on and move forward (even though some of that forward movent is through pounds we've already lost before). So, come on, Medibud! Let's hit this trail together! We can't change the past, but we have total control over right now!
(forgive the long post
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