Possible, but our food supply is already dwindling. This suggests a motivation beyond out gradual starvation. Is there a reason why the process would need to be accelerated?

As with the metaphorical frog in a slowly heating pot, perhaps we were not becoming aware of our situation quickly enough for our scientist captors. [He pauses, makes a face.] Either that, or they are preparing to subject us to something else that necessitates a low food supply.