Yes, its possible to eat little and not be hungry.
Some "brief" signs:
1. Low energy (low blood sugar), feeling of tiredness, sleepy (sleeplessness), etc
Long periods of eating dysfunctions, one's metabolism can down shift to compensate (dependent), and in severe cases, will not "eventually" compensate. And, dependent on personal particulars, one's body is having a "party" having itself for dinner.
2. Feeling of lethargy
4. Impacts mood, goal passion, and attitude.
5. Mental alertness
6. Headaches (also could be from too low of carbs)
7. Nervousness, shaky, slight tremors.
8. General day to day "feeling" swings (can impact one's psychology)
9. Weakened overall bodily strength and recovery
And, many other signs, dependent upon the serverity of food (nutrition) deprivation particular to the person.
Though the ones I listed can have a severe impact on an individual, these are mild to cases in the "extreme" side of the equation.