Ewest may be able to use his access to the literature to help some more with this. Cecil noted that the high carbohydrate diet is bad for the fish at least most fish. At this point I agree, but I am not a fish nutritionist. Mentioned earlier was complex carbohydrates are not digestible by fish. So if carbs as Cecil (via Dr.Brown)says are creating the excess fat, then the carbs must be simple digestible carbs that are the problem with the fish food creating excess fat. If the carbs are not digestible they will be passed and not create fat. From ewest's post the proper type of fat is also important for the health of at least some fish species; probably the low saturated fats are best.
Keep in mind two things. 1. We usually have ready access on only one type of fish food. So we feed the highest protein food that we have available regardless of the composition or brand.
2. Current diet content of commercial fish foods is to grow the fish quickest for a market harvest. This philosophy has no consideration for a long healthy life span for the fish to grow longer from large size to the trophy categories. Cecil, others, and I are seeing rapid growth of fish fed pellets which leads to early deaths or short life spans i.e. premature deaths. This is not a concern or goal of the fish food manufacturers; rapid growth to harvest size is the goal.
Back to the topic of what is the best food for winter foraging fish. I think it is a food or diet that mimics natural foods of fish in winter. Here is where ewest or others can help. What is the protein, carbohydrate, and fat content of BG, FHM or even common pond invertebrates eaten by most panfish? That composition will most likely be the best diet for sport fish in winter.
Here is a link to what is present in menhaden fish meal.
http://www.ingredients101.com/fishmeal.htmnote the protein and fat content. Fat is primarily fatty acids - oil consistency - unsaturated. Carbohydrates are not listed for menhaden meal.
