hi kkkkaty
briffa's book is a really good place to start with low-carbing, as you say it gives a really good background and argument for this way of eating (WOE). however, quite a few of us have found that while his eating plan guidelines are great for long-term health and maintenance, unless you are strict with the frequency and portion control of things like nuts it's not necessarily so great for weight loss. for many of us, the level of carbs in his plan is just a bit too high to be in ketosis (which is what we are aiming for on bootcamp)
that may not be the case for you, however, and you may find that if you 'just stop eating all pasta, bread, cake biscuits, grains, rice etc etc and stick to the guidelines of allowable/non-allowable foods in the Briffa book' that you lose weight at a rate that is satisfactory for you, and in a way that is sustainable in the long term too
one of the reasons why bootcamp starts with a two-week strict period (similar to atkins first stage) is to switch your body to burning fat for fuel, getting you used to low-carb eating and breaking the cravings for sweet flavours and carbs. if you don't do this, you might find it harder to stick to your new way of eating in the short and longterm, as you may well still crave carbs through experiencing continued blood sugar level changes
when you are at maintenance, the idea is that you reintroduce carbs slowly until you reach a level of carb intake where you maintain weight (rather than losing or gaining). for everyone this is a different level, and will probably also vary in terms of what type of carbs (e.g. root vegetables such as potatoes might be better tolerated than grains such as wheat, or things like sugar). while you are trying to lose weight too, real life interferes, and you may choose to mindfully go off-plan for reasons of politeness or celebrations etc - on infrequent occasions.
however, i don't think any of us who have been following a low-carb way of eating for a while would advise going off-plan, at least during weight-loss period, to the extent of eating potato and/or pizza every weekend. if you did, you would risk the following:
- gaining several lb (probably of water weight, but possibly fat too) which you would then spend the next week losing, only to do the same thing the following weekend. this is quite an unforgiving way of eating in that respect
- knocking yourself out of ketosis, so you stop burning fat, and it can take several days to get back there
- creating blood sugar highs and crashes, which will in turn lead to...
- reigniting carb cravings which make it harder to stick to the WOE in the longterm
- eating things which, if you've read briffa, you'll know don't actually do you a whole lot of good health-wise
- feeling bloated, sluggish and uncomfortable, and possibly interfering with sleep and hormones
regarding alcohol/wine, my understanding is that although it doesn't necessarily knock you out of ketosis (depending on the carb content of whatever it is you're drinking), but the body will burn alcohol for fuel as a first choice, which means that you're not burning fat. on bootcamp, we stop alcohol for two weeks. after that, you can have some low-carb alcohol, but not too frequently. some do have a glass or so a night, but they tend to be those who are maintaining weight rather than trying to lose
i hope this helps, please do ask any other questions