Is it worse to skip a meal because you're simply not hungry or to eat a meal when you aren't hungry?

It depends: It depends on your overall situation. If you have normal appetite, are in good health, and have not been using drugs or other substances, skipping a meal when you're not hungry is probably okay. If you have medical illnesses or treatments that interfere with eating, or your appetite has been impaired for some time, skipping meals may not be good for you -- and you may need to eat anyway.

Better to eat.: Smaller frequent meals through the day would be the rule. Better to keep a steady stream of calories coming in. With skipping meals, you'll tend to eat larger meals thereafter, leading to weight gain.