Switching from FB Fit/Burn to FB30?


I've been doing FB30 for the last 3 months (I'm close to completing the programme for the second time). I chose FB30 because I don't have more time to work out than those 30-40 minutes a day.

However, with Christmas approaching (and all those dinners, lunches, teas, cookies...) and my schedule being less busy, I'd like to start someting more challenging, like FB Burn or FB Fit, also in the interest of not gaining weight and possibly losing a couple of kilos.

I'm worried that when I'll switch again from FB Burn/Fit to FB30 (like it's bound to happen in March, because of my schedule getting busier again), my body will not react well to the reduced workouts.

Have you had any experience with such a switch? Can you give suggestions?