I am not going to be much kinder about beer. In my view, it is a drink to be consumed in the strictest moderation.
Just as you may know skinny people who incessantly stuff themselves with bad carbohydrates with no ill effect, you have probably also met heavy beer drinkers with stomachs as flat as a pancake. (The wife of one of my best friends falls into this category.)
You do not need to have visited Germany to know about the usual side-effects of beer drinking, though : bloating, weight gain, bad breath and indigestion, all of which occur despite the presence of diastases (small enzymes whose function is to aid digestion). Let us just say that without diastases the consequences of beer drinking would be catastrophic.
Beer contains everything that is bad for you : alcohol (albeit in moderate quantities), gas and, above all, a large amount (4g per litre) of a carbohydrate called maltose, whose glycaemic index is 110, higher even than that of glucose. Furthermore, the combination of alcohol and sugar tends to lead to hypoglycaemia, and therefore tiredness and under-performance (see chapter on hypoglycaemia). So it is a drink with high energy potential, which means a high potential for creating stored fat.
You should give up beer, especially between meals. If you really cannot resist it, consider beer in the same way you consider chips. Indulge yourself once or twice a year, by having a pint or two of the best beer your local can provide, but make sure you choose a quality brew.
In Phase I, I would advise you to drink no beer at all. In Phase II, though, just as you can reintroduce wine in moderation, so you can, from time to time, enjoy a small quantity (33 centilitres at most) of beer with a meal.