Two points: with different levels of hydration, your body weight can vary and hence your BF % (plus if you use electro-impedance measurement, it changes your conductivity). I'm sure many of us have noticed that you drop a lot of weight after intense exercise. I drop about 5lbs after an hour of hockey and that's not fat or muscle disappearing - it's water. Even sleeping, I drop around 3lbs. So small changes in BF are insignificant.
On the bulking diet, I'm trying to follow Zone principles but with increased protein and fat. Here's the mix from 2 days ago (www.fitday.com
is a great way to measure this, thanks to Chris Forbis for the suggestion). First column is grams and second is calories.
Fat: 228g 2051c 47%
Sat: 61 550 13%
Poly: 26 233 5%
Mono: 122 1097 25%
Carbs: 285 961 22%
Fiber: 44 0 0%
Protein: 259 1035 24%
By my rough calculation, that's around 70 fat blocks, 29 carb blocks and 35 protein blocks.
Clearly there's enough protein for muscle growth and enough carbs for energy. The fat is mostly monosaturated from olive oil. My theory is that when I want to go back to leaning out, it will be easy to drop the fat back down: I never get cravings for olive oil and my stomach won't have expanded to accommodate the bulk of food I'd be eating if I relied on carbs for the increase. And of course the Zone would say that the fat is less likely to convert to body fat.