Word to describe something as inadequately small in comparison
Solution 1:
Consider: measly.
I was just reading Kory Stamper's Word by Word in which she describes her experiences as a lexicographer at Merriam-Webster. She described needing to differentiate "measly" from other types of "small" and provided this footnote:
"Measly" is defined in the Collegiate Dictionary, Eleventh Edition, as "contemptibly small." Emily Brewster thinks it might be the best definition in the whole book.
"Contemptibly small" does match the meaning implied in the example sentence of the OP question. It also matches the emotional context of "food scraps" and "leftovers." I'm not so sure it matches the "inadequate" criterion in the title.
Solution 2:
Most of these answers provide terms that describe poor quality, but don't address the comparative element of the question. This could be a problem if both items being compared are valuable on their own and you're just trying to point out that one is much more valuable than the other.
One term for describing one thing as being less valuable than another without making any implications about its objective value is to describe the former as inferior to the latter, e.g. "Mine is the perfect gift; yours is inferior."
If you can accept a phrase, then consider describing the lesser item as paling in comparison to the greater. For example, "Your gift pales in comparison to mine." This alludes to the appearance of one item seeming less vivid and appealing than another when the two are held side-by-side, as the latter is more vivid and the eye/brain adjusts to hold the former item to that standard.
Solution 3:
You might consider pathetic, as per item 2 in this list from Oxford Dictionaries
pathetic
- Arousing pity, especially through vulnerability or sadness.
‘she looked so pathetic that I bent down to comfort her’- informal Miserably inadequate.
‘he's a pathetic excuse for a man’- archaic Relating to the emotions.