Fire Crystal
1 x Maple Sugar
1 x Olive Oil
1 x Rock Salt
1 x Imperial Flour
1 x Cockatrice Meat
1 x Distilled Water
1 x Apkallu Egg
1 x Grauberg Lettuce
At 120 BLU skill I'm getting .3 to .5 every 3rd spell, just casting pollen and wild carrot on myself. I don't think this is an "offensive magic" only food.
THese are ment for offensive magic skill ups there is also a food for non offensive magic skill ups which explains why you are not seeing skill ups from eating eating these. You want stuffed Pitaru, not poultry.
Original post: From using this with barspells (leveling enhancing magic) I believe the food does not increase the frequency of skill ups but rather has a chance to increase the amount of skill gained per skill up. I was getting 0.4's and 0.5's all the time with the food on. I think the highest I got without it was 0.3. This is from hours and hours of casting so I believe this observation is fairly accurate.
New post: Continuing to skill enhancing magic and it doesn't actually seem to increase the amount of skill gained. I guess it increases rate of skill ups, but the difference is not really noticeable.