At 250 calories for a day's supply of the pills, you will be getting less than 1/10 of a normal adult intake. You would still be starving on this, but you would at least be starving more slowly. I think it is roughly equivalent to taking a daily multivitamin pill and some protein powder (or powdered milk).

If you tripled the pill ration and supplemented it with a starchy staple such as rice, bread, potatoes or corn, etc. then you could probably maintain your weight, energy and health reasonably well for a while on it. You would still be lacking fibre and probably calcium as well as other things, though, so this would not exactly be ideal in the long-term.

The packaging is pretty neat, though.