I personally like to see more of the food in focus and will use a smaller aperture setting in order to achieve a wider depth of field (I hope I got this the right way round). For me, food pictures taken in dark restaurants comes down to a trade-off of camera settings to get the exposure and picture clarity. The trade-off in a dark restaurant is having to increase the ISO (and dealing with noise) or opening the shutter for longer (and perhaps getting a shaky picture).
From experience, I know I like food pictures at an aperture of f/4.5. That gets enough of the food in focus for me for me to want to lick my screen.
These were taken in Hollywood Brown Derby.
I set my aperture to f/4.5 for these. I had to up the ISO to 3200 in HBD.
For me, f/4.5 will keep most of the picture in focus and some clarity lost due to depth of field. But I like my food pictures like that. I have tried taking pictures with a larger aperture and there isn't enough of food in focus for me.
I find shooting steak a challenge. The darkness of the meat can make it difficult to see it properly. I personally don't like using a flash with food pictures; so I will accept with the lack of clarity in the meat. One day, I'll learn to take better dynamic range shots.
If I up the ISO or keep the shutter open for longer, I end up with a picture not quite in focus or noisy. So, it is a trade-off.
Here's dessert from the HBD meal. Shutter speeds were around 1/25 - 1/30 here. So, some are a little blurry.
(No cringing please, or if you do....I don't really wanna know

)
These were from Cali Grill; where there was more natural light.
Aperture of f/4.5. ISO 640 - 1600, as the light changed.
In the end, it will come down to your preference for how you want your food pictures to look as to which camera settings you'll end up favouring.
Good luck with it and I hope you'll come back and post some of your shots here.
