Ascorbic acid seems to be involved in carbohydrate metabolism, or at least in glucose metabolism, which may be why the small amounts of vitamin C in an all meat diet seem to be sufficient to avoid scurvy—negligible carbohydrate intake means reduced levels of vitamin C. Both raw unfiltered honey and fruits seem like they don’t cause the kind of metabolic derangement attributed to foods high in refined carbohydrates like refined grains and sugar. Empirically high-carbohydrate foods in the ancestral diet are usually high in vitamin C. Honey seems like an exception, but there might be other poorly understood micronutrients in it that help as well. So it seems probable but not certain that taking in a lot of carbohydrates without a corresponding increase in vitamin C (and/or possibly other micronutrients they tend to come with in fresh fruit) could lead to problems.
Seeds (including grains) also tend to have high concentrations of antinutrients, plant defense chemicals, and hard to digest or allergenic proteins (these are not mutually exclusive categories), so it might be problematic in the long run to get a large percentage of your calories from cake for that reason. Additionally, some B vitamins like thiamine are important for carbohydrate metabolism, so if your sponge cake is not made from a fortified flour, you may want to take a B vitamin supplement.
Finally, sponge cake can be made with or without a variety of adulterants and preservatives, and with higher-quality or lower-quality fats. There is some reason to believe that seed and vegetable oils are particularly prone to oxidation and may activate torporific pathways causing lower energy and favoring accumulation of body fat over other uses for your caloric intake, but I haven’t investigated enough to be confident that this is true.
I wouldn’t recommend worrying about glycemic index, as it’s not clear high glycemic index causes problems. If your metabolism isn’t disordered, your pancreas should be able to release an appropriate amount of insulin, causing the excess blood sugar to be stored in fat or muscle cells. If it is disordered, I’d prioritize fixing that over whatever you’re trying to do with a “bulk.” Seems worth reflecting on the theory behind a “bulk,” though, as if you’re trying to increase muscle mass, I think the current research suggests that you want to:
Take in enough protein
Take in enough leucine at one time to trigger muscle protein synthesis
Take in enough calories to sustain your activity level
Ascorbic acid seems to be involved in carbohydrate metabolism, or at least in glucose metabolism, which may be why the small amounts of vitamin C in an all meat diet seem to be sufficient to avoid scurvy—negligible carbohydrate intake means reduced levels of vitamin C. Both raw unfiltered honey and fruits seem like they don’t cause the kind of metabolic derangement attributed to foods high in refined carbohydrates like refined grains and sugar. Empirically high-carbohydrate foods in the ancestral diet are usually high in vitamin C. Honey seems like an exception, but there might be other poorly understood micronutrients in it that help as well. So it seems probable but not certain that taking in a lot of carbohydrates without a corresponding increase in vitamin C (and/or possibly other micronutrients they tend to come with in fresh fruit) could lead to problems.
Seeds (including grains) also tend to have high concentrations of antinutrients, plant defense chemicals, and hard to digest or allergenic proteins (these are not mutually exclusive categories), so it might be problematic in the long run to get a large percentage of your calories from cake for that reason. Additionally, some B vitamins like thiamine are important for carbohydrate metabolism, so if your sponge cake is not made from a fortified flour, you may want to take a B vitamin supplement.
Finally, sponge cake can be made with or without a variety of adulterants and preservatives, and with higher-quality or lower-quality fats. There is some reason to believe that seed and vegetable oils are particularly prone to oxidation and may activate torporific pathways causing lower energy and favoring accumulation of body fat over other uses for your caloric intake, but I haven’t investigated enough to be confident that this is true.
I wouldn’t recommend worrying about glycemic index, as it’s not clear high glycemic index causes problems. If your metabolism isn’t disordered, your pancreas should be able to release an appropriate amount of insulin, causing the excess blood sugar to be stored in fat or muscle cells. If it is disordered, I’d prioritize fixing that over whatever you’re trying to do with a “bulk.” Seems worth reflecting on the theory behind a “bulk,” though, as if you’re trying to increase muscle mass, I think the current research suggests that you want to:
Take in enough protein
Take in enough leucine at one time to trigger muscle protein synthesis
Take in enough calories to sustain your activity level