According to my sources 饣 means "food" or "eat". Since when do people eat jewelry?
饣 is the phonetic, not the signific.
饣, which is simplified from
食, is the radical of
飾 only in the sense that it is listed that way in a Chinese dictionary. It is not the meaning-bearing part of the character. Here are two possible analyses. In both cases,
饣 is contributing to the pronunciation, not the meaning:
飾 = 食 (phonetic: shi2) + 布 (signific: cloth)
飾 = 飤 (phonetic: si4) + 巾 (signific: cloth)
飾 = 食 (phonetic: shi2) + [人 + 巾] (signific: person + cloth)
The first analysis might seem the most plausible, given the character's present appearance, but if you look at the seal script forms for 飾 and for 布, you'll see that the right side of
飾doesn't really look much like
The second analysis has the appeal that it's a simple phonetic + signific, but @Claw points out that both
食are checked-syllables in Cantonese, while
飤is not. This indicates that
食is a much better phonetic match to
As alluded to in 1, the right side (in seal script) doesn't look like
布, it looks like
人-like fragment. As pointed out by another answerer, cloth+person is a good signific for "decorate".
Edit: Added analysis #3, which Claw suggests is the most plausible, incorporating his arguments.
According to zdic.net, 饰 is formed of 巾, 人, and 食 (饣). 食 (饣) is the sound component, while the other portion suggests the meaning.
The dictionary explains the character's components this way: 形声。从巾,从人,食声。人佩巾有装饰作用。 So, it's a 'pictophonetic' character which signifies a person wearing or adorned with a cloth, thus having the effect of decoration.
If you're interested in this kind of composition theory, you can look up more on the various ways characters were composed. 形声 being one of the ways.
Zdic.net is great for this kind of thing. When you look up a character or word you can click 详细解释 for more in-depth info. Yellowbridge is also decent for this kind of question.
Let me connect the dots for @EdenHarder (but comment box is too narrow...)
Signific or phonetic, imagine in an ancestor worship or toward a deity in ancient times (e.g. Shang), people present with food, covered with cloth; or people wearing cloth present it, such that 飾 follows巾 and 人, pronounced as 食, similar to the pronunciation of 式, also known as 襐飾 (xiang4 shi4); its consonant same as 賞, vowel same as 隻.
Welcome further enquiry with all respect.
 漢韓大字典，民衆書林，2013年1月10日 第3版 第6刷 發行，ISBN 978-89-387-0148-0. Chinese-Korean Dictionary, Minjungseorim Co., January 10 2013 3rd edition 6th print.
 說文解字 大徐本，許慎
Ministry of Education, Taiwan, tells us that 飾乃刷洗清潔之意 通「拭」如 周禮．地官．封人：「凡祭祀 飾其牛牲」參見此處