Short answer
Various inhalants, most notably organic solvents including those used in paint and glue suppress appetite.
Background
From the Division of Alcohol and Drug Abuse I learned the following:
Initial effects [of various inhalants] include nausea [...], and a loss of appetite.
And the Humanitarian Irin News reports the following on Nepali street youths:
The adhesive glue contains toluene, [an] intoxicating hydrocarbon [...]. The solvent [...] causes hallucinations as well as dampening hunger pangs [...].
Indeed, acute exposure to organic solvents has been associated with a loss of appetite (Gregerson, 1998), and chronic exposure to toluene in the industrial workforce has also been linked to appetite suppression (Kishi et al., 1993).
References
- Gregerson, Am J Industr Med (1998); 14(6): 681–701
- Kishi et al., Environmental Res (1993); 62(2): 303–13