Well, as someone who gave up sugar and starch completely for a complete year and can still remember the awfulness of that Thanksgiving and Christmas, I have to say I will be enjoying my sugary foods this year into the holidays!
Even when I did "Christmas and Thankgiving" are "eat what you want days" while stringently eliminating starch and sugar the rest of the time, it was still a problem, because I was looking forward so much to eating the traditional holiday treats that when someone didn't bring something to the dinner that I had been looking forward to, I felt a huge burst of deprivation that made me both sad and resentful. A 50-ish women in tears because she didn't get to eat a chocolate truffle on Christmas morning is nothing you ever want to see--or be.
So hard won experience has taught me that it is much better to aim for moderating your intake of sugar rather than eliminating it. It's much tougher to do that, but the payoff is that you will lose that intensely emotional love/hate relationship with sweets that leads to the almost inevitable binging that follows total denial.
What I love about 5:2 is that I am not going to extremes or imposing my idea of perfect nutrition on myself or on others, the way I have done on earlier, more stringent but no more effective diets. And as I have allowed myself the freedom to eat without all that compulsivity, I have noticed that my eating on non-fasting days has become far more reasonable.
One thing that I love about 5:2 is that this is the first long-term diet I've been on where I don't have dreams in which I'm consuming all the forbidden foods I'm not allowed to eat on my diet. These were a constant feature of my low carb diet days and I'm very glad to see the last of them.
And the weight loss and health results of this diet appear to be the same or better than my low carb diet, which is very interesting indeed. My fasting blood sugar is lower than it usually is on a very low carb diet and my blood sugars after eating even very carby meals are in the normal range as long as I take my metformin, but I was taking the metformin while eating low carb, too. Best of all, my blood pressure is looking a lot better, though I won't know if that is permanent until it gets cold, as my BP usually surges in December and stays bad until spring.
So while I'm happy to join a Christmas challenge, it will be a "eat like an ordinary person five days of the week and fast on two" challenge. If I manage to shift a pound or two, that would be delightful, but mostly I just want to be able to get through the holidays not packing on five pounds.