Oops, I forgot to write on what I found in the beta. @zaffy2005 Thank you for bumping this thread
Food type materials are used to create food items at food stand (『PSO2 NEW GENESIS Prologue 1』(12/19/2020)).
At least in JP CBT2, various food materials were not tradable on the N-personal shops (and remember, direct player-to-player trading is totally prohibited in NGS). So basically, we had to gather these materials on our own. The boost effect from food items last for two hours and based on the categories and taste types of the materials used.
There are four categories of foods, meat, seafood, fruit and vegetable. Among these, meat items can be gathered by killing tames. Materials of other three categories can be collected just by pressing "access" button near the collection point.
The taste type of food materials are defined by the item itself. Food items with the same item name always have the same taste type. For example, the apple item shown in the video above, always have "rich" taste type and "fruit" category (I dunno what each taste types are actually called in the English version).
When we create a boost food item from these materials, there are no fixed recipe which specify the exact number of items used (like what we have now in the original PSO2). Each food item category and each taste type have associated boost effects, using an item as a material simply adds the effect on the resulting boost food. Using more items strengthen the effect. For example, the video above used an apple and a certain meat as materials. The fruit category of apple boosts maximum PP and meat category boosts attack potency, so the boost food item made in the video had these two boost effects. The taste type boost effect only becomes active when four or more materials of the same taste are used, so didn't appear in this example.
So this went pretty long, but at last I can provide some answer to the OP. Not using meat category materials in the food stand means you won't be able to get the attack potency boost effect. At first glance, this might look as a greater disadvantage. Yet at least seeing from the balance in the JP beta test, the attack potency boost from the food didn't look that effective. Rather the max PP boost coming from the fruit category materials were much more effective. Using 1 fruit adds +10 PP, 2 fruits +11, 3 fruits +12 and so on. The +10 PP boost was so strong that it's almost a must to use at least one fruit when making a boost food item.
As a conclusion, banning a meat category material in cooking didn't seem to be a great disadvantage in the JP 2nd closed beta. But if SEGA adjusted the game balance in the future and made attack potency boost stronger, this might not hold true then.
As an additional note, even if the food materials are not tradable, actually we can get some meat items without killing tames with our own hands. As in the original PSO2, we can get drop items from enemies other players defeated. So if we play in the field with other players for a long time, we'll naturally get some meat materials as long as there are some tame hunters nearby.
Finally, in the CBT, there was one specific tutorial task requiring to defeat a tame and get a meat item from it. Maybe this will remain in the actual game too.