One month in - the cold and the fat?

So nearly 60km in the pool in January seems like a good base for my first month's serious training. Still a long way off what I should be building up to in Summer (at least twice that much). There are several issues that have occupied my thoughts though, the main one is the cold water acclimatisation. People have suggested that I need to start walking around in shorts and t-shirts in winter, sleeping under only a sheet etc. As the temperature this week plummeted well below freezing again I have not stuck to this philosophy with any enthusiasm. I have taken to running in the mornings without the gloves and hat that takes the edge off the cold and as I waded through the snow on top of Cleeve hill this morning I found myself questioning this decision also. The other part to this worry is the need to fatten up for the swim. How much fat is ideal when swimming the channel? I have read figures of about 15% body fat which is not a significant level. Pictures of the repeat swimmers of channel crossings tend to suggest that quite a bit more than that is not a disadvantage although there must be some trade off between extra weight and reduced fitness. I have not actively tried to bulk up too much yet, 78kg was my weight at the end of Jan and I am simply not being fussy at the moment about what I eat. I figured I could go up to 85kg quite happily, personally if the extra fat genuinely helps to keep out the cold I'll be more than happy to follow Renee Zellwinger's diet (in bulking up for Bridget Jones) and eat ice cream with every meal.